The Abbasid Caliphate (/əˈbæsɪd/ or /ˈæbəsɪd/ Arabic: ٱلْخِلافَةُ ٱلْعَبَّاسِيَّة‎, al-Khilāfatu al-ʿAbbāsiyyah) was the third of the Islamic caliphates to succeed the Islamic prophet Muhammad. It was founded by a dynasty descended from Muhammad's uncle, Abbas ibn Abdul-Muttalib (566–653 CE), from whom the dynasty takes its name.^[10] They ruled as caliphs for most of the caliphate from their capital in Baghdad in modern-day Iraq, after having overthrown the Umayyad Caliphate in the Abbasid Revolution of 750 CE (132 AH).

The Abbasid Caliphate first centred its government in Kufa, modern-day Iraq, but in 762 the caliph Al-Mansur founded the city of Baghdad, near the ancient Sasanian capital city of Ctesiphon. The Abbasid period was marked by reliance on Persian bureaucrats (notably the Barmakid family) for governing the territories as well as an increasing inclusion of non-Arab Muslims in the ummah (national community). Persianate customs were broadly adopted by the ruling elite, and they began patronage of artists and scholars.^[11] Baghdad became a centre of science, culture, philosophy and invention in what became known as the Golden Age of Islam.

Despite this initial cooperation, the Abbasids of the late 8th century had alienated both non-Arab mawali (clients)^[12] and Iranian bureaucrats.^[13] They were forced to cede authority over al-Andalus (Spain) to the Umayyads in 756, Morocco to the Idrisid dynasty in 788, Ifriqiya and Southern Italy to the Aghlabids in 800, Iran to Saffarid in 861 and Egypt to the Isma'ili-Shia caliphate of the Fatimids in 969.

The political power of the caliphs largely ended with the rise of the Iranian Buyids and the Seljuq Turks, who captured Baghdad in 945 and 1055, respectively. Although Abbasid leadership over the vast Islamic empire was gradually reduced to a ceremonial religious function, the dynasty retained control over its Mesopotamian domain. The Abbasids' period of cultural fruition ended in 1258 with the sack of Baghdad by the Mongols under Hulagu Khan. The Abbasid line of rulers, and Muslim culture in general, re-centred themselves in the Mamluk capital of Cairo in 1261. Though lacking in political power (with the brief exception of Caliph Al-Musta'in of Cairo), the dynasty continued to claim religious authority until after the Ottoman conquest of Egypt in 1517.^[14]

The Abbasid caliphs were Arabs descended from Abbas ibn Abd al-Muttalib, one of the youngest uncles of Muhammad and of the same Banu Hashim clan. The Abbasids claimed to be the true successors of Prophet Muhammad in replacing the Umayyad descendants of Banu Umayya by virtue of their closer bloodline to Muhammad.

The Abbasids also distinguished themselves from the Umayyads by attacking their moral character and administration in general. According to Ira Lapidus, "The Abbasid revolt was supported largely by Arabs, mainly the aggrieved settlers of Merv with the addition of the Yemeni faction and their Mawali".^[15] The Abbasids also appealed to non-Arab Muslims, known as mawali, who remained outside the kinship-based society of the Arabs and were perceived as a lower class within the Umayyad empire. Muhammad ibn 'Ali, a great-grandson of Abbas, began to campaign in Persia for the return of power to the family of Prophet Muhammad, the Hashimites, during the reign of Umar II.

During the reign of Marwan II, this opposition culminated in the rebellion of Ibrahim the Imam, the fourth in descent from Abbas. Supported by the province of Khorasan (Eastern Persia), even though the governor opposed them, and the Shia Arabs,^[10][16] he achieved considerable success, but was captured in the year 747 and died, possibly assassinated, in prison.

On 9 June 747 (15 Ramadan AH 129), Abu Muslim, rising from Khorasan, successfully initiated an open revolt against Umayyad rule, which was carried out under the sign of the Black Standard. Close to 10,000 soldiers were under Abu Muslim's command when the hostilities officially began in Merv.^[17] General Qahtaba followed the fleeing governor Nasr ibn Sayyar west defeating the Umayyads at the Battle of Gorgan, the Battle of Nahāvand and finally in the Battle of Karbala, all in the year 748.^[16]

The quarrel was taken up by Ibrahim's brother Abdallah, known by the name of Abu al-'Abbas as-Saffah, who defeated the Umayyads in 750 in the battle near the Great Zab and was subsequently proclaimed caliph.^[18] After this loss, Marwan fled to Egypt, where he was subsequently assassinated. The remainder of his family, barring one male, were also eliminated.^[16]

Immediately after their victory, As-Saffah sent his forces to Central Asia, where his forces fought against Tang expansion during the Battle of Talas. The noble Iranian family Barmakids, who were instrumental in building Baghdad, introduced the world's first recorded paper mill in the city, thus beginning a new era of intellectual rebirth in the Abbasid domain. As-Saffah focused on putting down numerous rebellions in Syria and Mesopotamia. The Byzantines conducted raids during these early distractions.^[16]

The first change the Abbasids, under Al-Mansur, made was to move the empire's capital from Damascus, in Syria, to Baghdad in Iraq. This was to both appease as well to be closer to the Persian mawali support base that existed in this region more influenced by Persian history and culture, and part of the Persian mawali demand for less Arab dominance in the empire. Baghdad was established on the Tigris River in 762. A new position, that of the vizier, was also established to delegate central authority, and even greater authority was delegated to local emirs.^[20]

This eventually meant that many Abbasid caliphs were relegated to a more ceremonial role than under the Umayyads, as the viziers began to exert greater influence, and the role of the old Arab aristocracy was slowly replaced by a Persian bureaucracy.^[20] During Al-Mansur's time control of Al-Andalus was lost, and the Shia revolted and were defeated a year later at the Battle of Bakhamra.^[16]

The Abbasids had depended heavily on the support of Persians^[10] in their overthrow of the Umayyads. Abu al-'Abbas' successor, Al-Mansur welcomed non-Arab Muslims to his court. While this helped integrate Arab and Persian cultures, it alienated many of their Arab supporters, particularly the Khorasanian Arabs who had supported them in their battles against the Umayyads.

These fissures in their support led to immediate problems. The Umayyads, while out of power, were not destroyed. The only surviving member of the Umayyad royal family, which had been all but annihilated, ultimately made his way to Spain where he established himself as an independent Emir (Abd ar-Rahman I, 756). In 929, Abd ar-Rahman III assumed the title of Caliph, establishing Al Andalus from Córdoba as a rival to Baghdad as the legitimate capital of the Islamic Empire.

In 756, the Abbasid Caliph Al-Mansur sent over 4,000 Arab mercenaries to assist the Chinese Tang dynasty in the An Shi Rebellion against An Lushan. The Abbasides or "Black Flags," as they were commonly called, were known in Tang dynasty chronicles as the hēiyī Dàshí, "The Black-robed Tazi", (黑衣大食) ("Tazi" being a borrowing from Persian Tāzī, the word for "Arab").^{[1][2][3][4][5]} Al-Rashid sent embassies to the Chinese Tang dynasty and established good relations with them.^{[26][6][7][29][30][31][32][33]} After the war, these embassies remained in China^{[34][35][36][37][38]} with Caliph Harun al-Rashid establishing an alliance with China.^[26] Several embassies from the Abbasid Caliphs to the Chinese court have been recorded in the T'ang Annals, the most important of these being those of Abul Abbas al-Saffah, the first Abbasid caliph, his successor Abu Jafar, and Harun al-Rashid.

The Abbasid leadership had to work hard in the last half of the 8th century (750–800), under several competent caliphs and their viziers to overcome the political challenges created by the far flung nature of the empire, and the limited communication across it and usher in the administrative changes needed to keep order.^[39] It was also during this early period of the dynasty, in particular during the governance of al-Mansur, Harun al-Rashid, and al-Ma'mun, that the reputation and power of the dynasty was created.^[10]

Al-Mahdi restarted the fighting with the Byzantines and his sons continued the conflict until Empress Irene pushed for peace.^[16] After several years of peace, Nikephoros I broke the treaty, then fended off multiple incursions during the first decade of the 9th century. These attacks pushed into the Taurus Mountains culminating with a victory at the Battle of Krasos and the massive invasion of 806, led by Rashid himself.^[40]

Rashid's navy also proved successful as he took Cyprus. Rashid decided to focus on the rebellion of Rafi ibn al-Layth in Khorasan and died while there.^[40] While the Byzantine Empire was fighting Abbasid rule in Syria and Anatolia, military operations during this period were minimal, as the caliphate focused on internal matters, its governors exerting greater autonomy and using their increasing power to make their positions hereditary.^[20]

At the same time, the Abbasids faced challenges closer to home. Harun al-Rashid turned on the Barmakids, a Persian family that had grown significantly in power within the administration of the state and killed most of the family.^[41] During the same period, several factions began either to leave the empire for other lands or to take control of distant parts of the empire away from the Abbasids. The reign of al-Rashid and his sons were considered to be the apex of the Abbasids.^[42]

After Rashid's death, the empire was split by a civil war between the caliph al-Amin and his brother al-Ma'mun who had the support of Khorasan. This war ended with a two-year siege of Baghdad and the eventual death of al-Amin in 813.^[40] Al-Ma'mun ruled for 20 years of relative calm interspersed with a rebellion supported by the Byzantines in Azerbaijan by the Khurramites. Al-Ma'mun was also responsible for the creation of an autonomous Khorasan, and the continued repulsing of Byzantine forays.^[40]

Al-Mu'tasim gained power in 833 and his rule marked the end of the strong caliphs. He strengthened his personal army with Turkish mercenaries and promptly restarted the war with the Byzantines. His military excursions were generally successful culminating with a resounding victory in the Sack of Amorium. His attempt at seizing Constantinople failed when his fleet was destroyed by a storm.^[43] The Byzantines restarted the fighting by sacking Damietta in Egypt. Al-Mutawakkil responded by sending his troops into Anatolia again, sacking and marauding until they were eventually annihilated in 863.^[44]

Even by 820, the Samanids had begun the process of exercising independent authority in Transoxiana and Greater Khorasan, as had the Twelver-Shia Hamdanids in Northern Syria, and the succeeding Tahirid and Saffarid dynasties of Iran. The Saffarids, from Khorasan, nearly seized Baghdad in 876, and the Tulunids took control of most of Syria. The trend of weakening of the central power and strengthening of the minor caliphates on the periphery continued.^[42]

An exception was the 10-year period of Al-Mu'tadid's rule (892–902). He brought parts of Egypt, Syria, and Khorasan back into the Abbasid's control. Especially after the "Anarchy at Samarra" (861–870), the Abbasid central government was weakened and centrifugal tendencies became more prominent in the Caliphate's provinces. By the early 10th century, the Abbasids almost lost control of Iraq to various amirs, and the caliph al-Radi was forced to acknowledge their power by creating the position of "Prince of Princes" (amir al-umara).^[42]

Al-Mustakfi had a short reign from 944–946, and it was during this period that the Persian faction known as the Buyids from Daylam swept into power and assumed control over the bureaucracy in Baghdad. According to the history of Miskawayh, they began distributing iqtas (fiefs in the form of tax farms) to their supporters. This period of localized secular control was to last nearly 100 years.^[10] The loss of Abbasid power to the Buyids would shift as the Seljuks would take over from the Persians.^[42]

At the end of the eighth century the Abbasids found they could no longer keep a huge polity larger than that of Rome together from Baghdad. In 793 the Zaydi-Shia dynasty of Idrisids set up a state from Fez in Morocco, while a family of governors under the Abbasids became increasingly independent until they founded the Aghlabid Emirate from the 830s. Al-Mu'tasim started the downward slide by utilizing non-Muslim mercenaries in his personal army. Also during this period officers started assassinating superiors with whom they disagreed, in particular the caliphs.^[10]

By the 870s, Egypt became autonomous under Ahmad ibn Tulun. In the East as well, governors decreased their ties to the center. The Saffarids of Herat and the Samanids of Bukhara had broken away from the 870s, cultivating a much more Persianate culture and statecraft. By this time only the central lands of Mesopotamia were under direct Abbasid control, with Palestine and the Hijaz often managed by the Tulunids. Byzantium, for its part, had begun to push Arab Muslims farther east in Anatolia.

By the 920s, the situation had changed further, as North Africa was lost to the Abbasids. A Shia sect only recognizing the first five Imams and tracing its roots to Muhammad's daughter Fatima took control of Idrisid and then Aghlabid domains.^[42] Called the Fatimid dynasty, they had advanced to Egypt in 969, establishing their capital near Fustat in Cairo, which they built as a bastion of Shia learning and politics. By 1000 they had become the chief political and ideological challenge to Sunni Islam in the form of the Abbasids. By this time the latter state had fragmented into several governorships that, while recognizing caliphal authority from Baghdad, did mostly as they wanted, fighting with each other. The Caliph himself was under 'protection' of the Buyid Emirs who possessed all of Iraq and western Iran, and were quietly Shia in their sympathies.

Outside Iraq, all the autonomous provinces slowly took on the characteristic of de facto states with hereditary rulers, armies, and revenues and operated under only nominal caliph suzerainty, which may not necessarily be reflected by any contribution to the treasury, such as the Soomro Emirs that had gained control of Sindh and ruled the entire province from their capital of Mansura.^[39] Mahmud of Ghazni took the title of sultan, as opposed to the "amir" that had been in more common usage, signifying the Ghaznavid Empire's independence from caliphal authority, despite Mahmud's ostentatious displays of Sunni orthodoxy and ritual submission to the caliph. In the 11th century, the loss of respect for the caliphs continued, as some Islamic rulers no longer mentioned the caliph's name in the Friday khutba, or struck it off their coinage.^[39]

The Isma'ili Fatimid dynasty of Cairo contested the Abbasids for even the titular authority of the Islamic ummah. They commanded some support in the Shia sections of Baghdad (such as Karkh), although Baghdad was the city most closely connected to the caliphate, even in the Buyid and Seljuq eras. The Fatimids' green banners contrasted with Abbasids' black, and the challenge of the Fatimids only ended with their downfall in the 12th century.

Despite the power of the Buyid amirs, the Abbasids retained a highly ritualized court in Baghdad, as described by the Buyid bureaucrat Hilal al-Sabi', and they retained a certain influence over Baghdad as well as religious life. As Buyid power waned with the rule of Baha' al-Daula, the caliphate was able to regain some measure of strength. The caliph al-Qadir, for example, led the ideological struggle against the Shia with writings such as the Baghdad Manifesto. The caliphs kept order in Baghdad itself, attempting to prevent the outbreak of fitnas in the capital, often contending with the ayyarun'

With the Buyid dynasty on the wane, a vacuum was created that was eventually filled by the dynasty of Oghuz Turks known as the Seljuqs. By 1055, the Seljuqs had wrested control from the Buyids and Abbasids, and took any remaining temporal power.^[10] When the amir and former slave Basasiri took up the Shia Fatimid banner in Baghdad in, the caliph al-Qa'im was unable to defeat him without outside help. Toghril Beg, the Seljuq sultan, restored Baghdad to Sunni rule and took Iraq for his dynasty.

Once again, the Abbasids were forced to deal with a military power that they could not match, though the Abbasid caliph remained the titular head of the Islamic community. The succeeding sultans Alp Arslan and Malikshah, as well as their vizier Nizam al-Mulk, took up residence in Persia, but held power over the Abbasids in Baghdad. When the dynasty began to weaken in the 12th century, the Abbasids gained greater independence once again.

While the Caliph al-Mustarshid was the first caliph to build an army capable of meeting a Seljuk army in battle, he was nonetheless defeated in 1135 and assassinated. The Caliph al-Muqtafi was the first Abbasid Caliph to regain the full military independence of the Caliphate, with the help of his vizier Ibn Hubayra. After nearly 250 years of subjection to foreign dynasties, he successfully defended Baghdad against the Seljuqs in the siege of Baghdad (1157), thus securing Iraq for the Abbasids. The reign of al-Nasir (d. 1225) brought the caliphate back into power throughout Iraq, based in large part on the Sufi futuwwa organizations that the caliph headed.^[42] Al-Mustansir built the Mustansiriya School, in an attempt to eclipse the Seljuq-era Nizamiyya built by Nizam al-Mulk.

In 1206, Genghis Khan established a powerful dynasty among the Mongols of central Asia. During the 13th century, this Mongol Empire conquered most of the Eurasian land mass, including both China in the east and much of the old Islamic caliphate (as well as Kievan Rus') in the west. Hulagu Khan's destruction of Baghdad in 1258 is traditionally seen as the approximate end of the Golden Age.^[45] Mongols feared that a supernatural disaster would strike if the blood of Al-Musta'sim, a direct descendant of Muhammad's uncle Al-‘Abbas ibn ‘Abd al-Muttalib,^[46] and the last reigning Abbasid caliph in Baghdad, was spilled. The Shia of Persia stated that no such calamity had happened after the death of Husayn ibn Ali in the Battle of Kerbala; nevertheless, as a precaution and in accordance with a Mongol taboo which forbade spilling royal blood, Hulagu had Al-Musta'sim wrapped in a carpet and trampled to death by horses on 20 February 1258. The Caliph's immediate family was also executed, with the lone exceptions of his youngest son who was sent to Mongolia, and a daughter who became a slave in the harem of Hulagu.^[47]

In the 9th century, the Abbasids created an army loyal only to their caliphate, composed of non-Arab origin people, known as Mamluks.^{[48][49][50][51][52]} This force, created in the reign of al-Ma'mun (813–33) and his brother and successor al-Mu'tasim (833–42), prevented the further disintegration of the empire. The Mamluk army, though often viewed negatively, both helped and hurt the caliphate. Early on, it provided the government with a stable force to address domestic and foreign problems. However, creation of this foreign army and al-Mu'tasim's transfer of the capital from Baghdad to Samarra created a division between the caliphate and the peoples they claimed to rule. In addition, the power of the Mamluks steadily grew until al-Radi (934–41) was constrained to hand over most of the royal functions to Muhammad ibn Ra'iq.^[18]

The Mamluks eventually came to power in Egypt. In 1261, following the devastation of Baghdad by the Mongols, the Mamluk rulers of Egypt re-established the Abbasid caliphate in Cairo. The first Abbasid caliph of Cairo was Al-Mustansir. The Abbasid caliphs in Egypt continued to maintain the presence of authority, but it was confined to religious matters. The Abbasid caliphate of Cairo lasted until the time of Al-Mutawakkil III, who was taken away as a prisoner by Selim I to Constantinople where he had a ceremonial role. He died in 1543, following his return to Cairo.

The Abbasid historical period lasting to the Mongol conquest of Baghdad in 1258 CE is considered the Islamic Golden Age.^[53] The Islamic Golden Age was inaugurated by the middle of the 8th century by the ascension of the Abbasid Caliphate and the transfer of the capital from Damascus to Baghdad.^[54] The Abbassids were influenced by the Qur'anic injunctions and hadith such as "the ink of a scholar is more holy than the blood of a martyr" stressing the value of knowledge. During this period the Muslim world became an intellectual center for science, philosophy, medicine and education as^[54] the Abbasids championed the cause of knowledge and established the House of Wisdom in Baghdad; where both Muslim and non-Muslim scholars sought to translate and gather all the world's knowledge into Arabic.^[54] Many classic works of antiquity that would otherwise have been lost were translated into Arabic and Persian and later in turn translated into Turkish, Hebrew and Latin.^[54] During this period the Muslim world was a cauldron of cultures which collected, synthesized and significantly advanced the knowledge gained from the ancient Roman, Chinese, Indian, Persian, Egyptian, North African, Greek and Byzantine civilizations.^[54] "In virtually every field of endeavor—in astronomy, alchemy, mathematics, medicine, optics and so forth—the Caliphate's scientists were in the forefront of scientific advance."^[55]

The reigns of Harun al-Rashid (786–809) and his successors fostered an age of great intellectual achievement. In large part, this was the result of the schismatic forces that had undermined the Umayyad regime, which relied on the assertion of the superiority of Arab culture as part of its claim to legitimacy, and the Abbasids' welcoming of support from non-Arab Muslims. It is well established that the Abbasid caliphs modeled their administration on that of the Sassanids.^[56] Harun al-Rashid's son, Al-Ma'mun (whose mother was Persian), is even quoted as saying:

A number of medieval thinkers and scientists living under Islamic rule played a role in transmitting Islamic science to the Christian West. In addition, the period saw the recovery of much of the Alexandrian mathematical, geometric and astronomical knowledge, such as that of Euclid and Claudius Ptolemy. These recovered mathematical methods were later enhanced and developed by other Islamic scholars, notably by Persian scientists Al-Biruni and Abu Nasr Mansur.

Christians (particularly Nestorian Christians) contributed to the Arab Islamic Civilization during the Ummayads and the Abbasids by translating works of Greek philosophers to Syriac and afterwards to Arabic.^[60][61] Nestorians played a prominent role in the formation of Arab culture,^[62] with the Jundishapur school being prominent in the late Sassanid, Umayyad and early Abbasid periods.^[63] Notably, eight generations of the Nestorian Bukhtishu family served as private doctors to caliphs and sultans between the eighth and eleventh centuries.^{[[64]](https://openlibrary.org/books/OL9611384M/Poverty_and_Charity_in_Middle_Eastern_Contexts_(Suny_Series_in_the_Social_and_Economic_History_of_th)[65]}

Algebra was significantly developed by Persian scientist Muhammad ibn Mūsā al-Khwārizmī during this time in his landmark text, Kitab al-Jabr wa-l-Muqabala, from which the term algebra is derived. He is thus considered to be the father of algebra by some,^[66] although the Greek mathematician Diophantus has also been given this title. The terms algorism and algorithm are derived from the name of al-Khwarizmi, who was also responsible for introducing the Arabic numerals and Hindu-Arabic numeral system beyond the Indian subcontinent.

Arab scientist Ibn al-Haytham (Alhazen) developed an early scientific method in his Book of Optics (1021). The most important development of the scientific method was the use of experiments to distinguish between competing scientific theories set within a generally empirical orientation, which began among Muslim scientists. Ibn al-Haytham's empirical proof of the intromission theory of light (that is, that light rays entered the eyes rather than being emitted by them) was particularly important. Alhazen was significant in the history of scientific method, particularly in his approach to experimentation,^[68] and has been referred to as the "world's first true scientist".^[69]

Medicine in medieval Islam was an area of science that advanced particularly during the Abbasids' reign. During the 9th century, Baghdad contained over 800 doctors, and great discoveries in the understanding of anatomy and diseases were made. The clinical distinction between measles and smallpox was described during this time. Famous Persian scientist Ibn Sina (known to the West as Avicenna) produced treatises and works that summarized the vast amount of knowledge that scientists had accumulated, and was very influential through his encyclopedias, The Canon of Medicine and The Book of Healing. The work of him and many others directly influenced the research of European scientists during the Renaissance.

Astronomy in medieval Islam was advanced by Al-Battani, who improved the precision of the measurement of the precession of the Earth's axis. The corrections made to the geocentric model by al-Battani, Averroes, Nasir al-Din al-Tusi, Mo'ayyeduddin Urdi and Ibn al-Shatir were later incorporated into the Copernican heliocentric model.^[70] The astrolabe, though originally developed by the Greeks, was developed further by Islamic astronomers and engineers, and subsequently brought to medieval Europe.

Muslim alchemists influenced medieval European alchemists, particularly the writings attributed to Jābir ibn Hayyān (Geber). A number of chemical processes such as distillation techniques were developed in the Muslim world and then spread to Europe.

The best known fiction from the Islamic world is The Book of One Thousand and One Nights, a collection of fantastical folk tales, legends and parables compiled primarily during the Abbassid era. The collection is recorded as having originated from an Arabic translation of a Sassanian era Persian prototype, with likely origins in Indian literary traditions. Stories from Arabic, Persian, Mesopotamian, and Egyptian folklore and literature were later incorporated. The epic is believed to have taken shape in the 10th century and reached its final form by the 14th century; the number and type of tales have varied from one manuscript to another.^[71] All Arabian fantasy tales were often called "Arabian Nights" when translated into English, regardless of whether they appeared in The Book of One Thousand and One Nights.^[71] This epic has been influential in the West since it was translated in the 18th century, first by Antoine Galland.^[72] Many imitations were written, especially in France.^[73] Various characters from this epic have themselves become cultural icons in Western culture, such as Aladdin, Sinbad and Ali Baba.

A famous example of Islamic poetry on romance was Layla and Majnun, an originally Arabic story which was further developed by Iranian, Azerbaijani and other poets in Persian, Azerbaijani, Turkish languages.^[74] It is a tragic story of undying love much like the later Romeo and Juliet.

Arabic poetry reached its greatest height in the Abbasid era, especially before the loss of central authority and the rise of the Persianate dynasties. Writers like Abu Tammam and Abu Nuwas were closely connected to the caliphal court in Baghdad during the early 9th century, while others such as al-Mutanabbi received their patronage from regional courts.

One of the common definitions for "Islamic philosophy" is "the style of philosophy produced within the framework of Islamic culture."^[75] Islamic philosophy, in this definition is neither necessarily concerned with religious issues, nor is exclusively produced by Muslims.^[75] Their works on Aristotle was a key step in the transmission of learning from ancient Greeks to the Islamic world and the West. They often corrected the philosopher, encouraging a lively debate in the spirit of ijtihad. They also wrote influential original philosophical works, and their thinking was incorporated into Christian philosophy during the Middle Ages, notably by Thomas Aquinas.

Three speculative thinkers, al-Kindi, al-Farabi, and Avicenna, combined Aristotelianism and Neoplatonism with other ideas introduced through Islam, and Avicennism was later established as a result. Other influential Abbasid philosophers include al-Jahiz, and Ibn al-Haytham (Alhacen).

As the power shifted from the Umayyads to the Abbasids, the architecture styles changed also. The Christian styles evolved into a style based more on the Sasanian Empire utilizing mud bricks and baked bricks with carved stucco.^[76] Another major development was the creation or vast enlargement of cities as they were turned into the capital of the empire. First, starting with the creation of Baghdad, starting in 762, which was planned as a walled city with a mosque and palace in the center. The walls were to have four gates to exit the city. Al-Mansur, who was responsible for the creation of Baghdad, also planned the city of Raqqa, along the Euphrates. Finally, in 836, al-Mu'tasim moved the capital to a new site that he created along the Tigris, called Samarra. This city saw 60 years of work, with race-courses and game preserves to add to the atmosphere.^[76] Due to the dry remote nature of the environment, some of the palaces built in this era were isolated havens. Al-Ukhaidir Fortress is a fine example of this type of building which has stables, living quarters, and a mosque, all surrounding inner courtyards.^[76] Other mosques of this era, such as the Mosque of Ibn Tulun, in Cairo, and the Great Mosque of Kairouan in Tunisia while ultimately built during the Umayyad dynasty, it was substantially renovated in the 9th century. This renovation was so extensive as to ostensibly be a rebuild, was in the furthest reaches of the Muslim world, in an area that the Aghlabids controlled; however the styles utilized were mainly of the Abbasids.^[77] Mesopotamia only has one surviving mausoleum from this era, in Samarra. This octagonal dome is the final resting place of al-Muntasir.^[78] Other architectural innovations and styles were few, such as the four-centered arch, and a dome erected on squinches. Unfortunately, much was lost due to the ephemeral nature of the stucco and luster tiles.^[78]

The Near East has, since Roman times, been recognized as a center of quality glassware and crystal. 9th century finds from Samarra show styles similar to Sassanian forms. The types of objects made were bottles, flasks, vases, and cups utilized for domestic use. Decorations on these domestic items include molded flutes, honeycomb patterns, and inscriptions.^[79] Other styles seen that may not have come from the Sassanians were stamped items. These were typically round stamps, such as medallions or disks with animals, birds, or Kufic inscriptions. Colored lead glass, typically blue or green, have been found in Nishapur, along with prismatic perfume bottles. Finally, cut glass may have been the high point of Abbasid glass-working, decorated with floral and animal designs.^[80]

Early Abbasid painting has not survived in great quantities, and sometimes harder to differentiate; however Samarra is a good example as it was built by the Abbasids and abandoned 56 years later. The walls of the principal rooms of the palace that has been excavated show wall paintings and lively carved stucco dadoes. The style is obviously adopted with little variation from Sassanian art, as not only the styles is similar with harems, animals, and dancing people, all enclosed in scrollwork, but also the garments are Persian.^[81] Nishapur had its own school of painting. Excavations at Nishapur show artwork both monochrome and polychrome from the 8th and 9th centuries. One famous piece of art consists of hunting nobles with falcons and on horseback, in full regalia; the clothing identifies him as Tahirid, which was again, a sub-dynasty of the Abbasids. Other styles are of vegetation, and fruit in nice colors on a four-foot high dedo.^[81]

Whereas painting and architecture were not areas of strength for the Abbasid dynasty, pottery was a different story. The Islamic culture as a whole and the Abbasid's, in particular, were at the forefront of new ideas and techniques. Some examples of their work were pieces engraved with decorations and then colored with yellow-brown, green, and purple glazes. Designs were diverse with geometric patterns, Kufic lettering, arabesque scrollwork, along with rosettes, animals, birds, and humans.^[82] Abbasid pottery from the 8th and 9th centuries have been found throughout the region, as far as Cairo. These were generally made with a yellow clay and fired multiple times with separate glazes to produce metallic luster in shades of gold, brown, or red. By the 9th century, the potters had mastered their techniques and their decorative designs could be divided into two styles. The Persian style would show animals, birds, humans, along with Kufic lettering in gold. Pieces excavated from Samarra exceed in vibrancy and beauty any from later periods. These predominantly being made for the Caliphs use. Tiles were also made utilizing this same technique to create both monochromic and polychromic luster tiles.^[83]

Egypt being a center of the textile industry was part of the Abbasid cultural advancement. Copts were employed in the textile industry and produced linens and silks. Tinnis was famous for its factories and had over 5,000 looms. Kasab, a fine linen for turbans and badana for garments of the upper class to name a couple. In a town named Tuna near Tinnis, was made the kiswah for the kaaba in Mecca. Fine silk was also made in Dabik and Damietta.^[84] Of particular interest is the stamped and inscribed fabrics. Not only did they utilize inks but also liquid gold. Some of the finer pieces were colored in such a manner as to require six separate stamps to achieve the proper design and color. This technology spread to Europe eventually.^[85]

In technology, the Abbasids adopted papermaking from China.^[86] The use of paper spread from China into the caliphate in the 8th century CE, arriving in al-Andalus (Islamic Spain) and then the rest of Europe in the 10th century. It was easier to manufacture than parchment, less likely to crack than papyrus, and could absorb ink, making it ideal for making records and making copies of the Koran. "Islamic paper makers devised assembly-line methods of hand-copying manuscripts to turn out editions far larger than any available in Europe for centuries."^[87] It was from the Abbasids that the rest of the world learned to make paper from linen.^[88] The knowledge of gunpowder was also transmitted from China via the caliphate, where the formulas for pure potassium nitrate and an explosive gunpowder effect were first developed.^[89]

Advances were made in irrigation and farming, using new technology such as the windmill. Crops such as almonds and citrus fruit were brought to Europe through al-Andalus, and sugar cultivation was gradually adopted by the Europeans. Apart from the Nile, Tigris and Euphrates, navigable rivers were uncommon, so transport by sea was very important. Navigational sciences were highly developed, making use of a rudimentary sextant (known as a kamal). When combined with detailed maps of the period, sailors were able to sail across oceans rather than skirt along the coast. Abbasid sailors were also responsible for reintroducing large three masted merchant vessels to the Mediterranean. The name caravel may derive from an earlier Arab ship known as the qārib.^[90] Arab merchants dominated trade in the Indian Ocean until the arrival of the Portuguese in the 16th century. Hormuz was an important center for this trade. There was also a dense network of trade routes in the Mediterranean, along which Muslim countries traded with each other and with European powers such as Venice or Genoa. The Silk Road crossing Central Asia passed through Abbasid caliphate between China and Europe.

Engineers in the Abbasid caliphate made a number of innovative industrial uses of hydropower, and early industrial uses of tidal power, wind power, and petroleum (notably by distillation into kerosene). The industrial uses of watermills in the Islamic world date back to the 7th century, while horizontal-wheeled and vertical-wheeled water mills were both in widespread use since at least the 9th century. By the time of the Crusades, every province throughout the Islamic world had mills in operation, from al-Andalus and North Africa to the Middle East and Central Asia. These mills performed a variety of agricultural and industrial tasks.^[86] Abbasid engineers also developed machines (such as pumps) incorporating crankshafts, employed gears in mills and water-raising machines, and used dams to provide additional power to watermills and water-raising machines.^[92] Such advances made it possible for many industrial tasks that were previously driven by manual labour in ancient times to be mechanized and driven by machinery instead in the medieval Islamic world. It has been argued that the industrial use of waterpower had spread from Islamic to Christian Spain, where fulling mills, paper mills, and forge mills were recorded for the first time in Catalonia.^[93]

A number of industries were generated during the Arab Agricultural Revolution, including early industries for textiles, sugar, rope-making, matting, silk, and paper. Latin translations of the 12th century passed on knowledge of chemistry and instrument making in particular.^[94] The agricultural and handicraft industries also experienced high levels of growth during this period.^[95]

In contrast to the earlier era, women in Abbasid society were absent from all arenas of the community's central affairs.^[96] While their Muslim forbearers led men into battle, started rebellions, and played an active role in community life, as demonstrated in the Hadith literature, Abbasid women were ideally kept in seclusion. Conquests had brought enormous wealth and large numbers of slaves to the Muslim elite. The majority of the slaves were women and children,^[97] many of whom had been dependents or harem-members of the defeated Sassanian upper classes.^[98] In the wake of the conquests an elite man could potentially own a thousand slaves, and ordinary soldiers could have ten people serving them.^[97]

Nabia Abbott, preeminent historian of elite women of the Abbasid Caliphate, describes the lives of harem women as follows.

The marketing of human beings, particularly women, as objects for sexual use meant that elite men owned the vast majority of women they interacted with, and related to them as would masters to slaves.^[99] Being a slave meant relative lack of autonomy during this time period, and belonging to a harem caused a wife and her children to have little insurance of stability and continued support due to the volatile politics of harem life.

Elite men expressed in literature the horror they felt for the humiliation and degradation of their daughters and female relatives. For example, the verses addressed to Hasan ibn al-Firat on the death of his daughter read:

Even so, courtesans and princesses produced prestigious and important poetry. Enough survives to give us access to women's historical experiences, and reveals some vivacious and powerful figures, such as the Sufi mystic Raabi'a al-Adwiyya (714–801 CE), the princess and poet 'Ulayya bint al-Mahdi (777–825 CE), and the singing-girls Shāriyah (c. 815–70 CE), Fadl Ashsha'ira (d. 871 CE) and Arib al-Ma'muniyya (797–890 CE).^[101]

While the Abbasids originally gained power by exploiting the social inequalities against non-Arabs in the Umayyad Empire, during Abbasid rule the empire rapidly Arabized, particularly in the Fertile Crescent region (namely Mesopotamia and the Levant) as had begun under Umayyad rule. As knowledge was shared in the Arabic language throughout the empire, many people from different nationalities and religions began to speak Arabic in their everyday lives. Resources from other languages began to be translated into Arabic, and a unique Islamic identity began to form that fused previous cultures with Arab culture, creating a level of civilization and knowledge that was considered a marvel in Europe at the time.^[102]

In Baghdad there were many Abbasid military leaders who were or said they were of Arab descent. However, it is clear that most of the ranks were of Iranian origin, the vast majority being from Khorasan and Transoxania, not from western Iran or Azerbaijan.^[103] with most of the Khorasani soldiers who brought the Abbasids to power were Arabs.^[104]

The standing army of the Muslims in Khurasan was overwhelmingly Arab. The unit organization of the Abbasids was designed with the goal of ethnic and racial equality among supporters. When Abu Muslim recruited officers along the Silk Road, he registered them based not on their tribal or ethno-national affiliations but on their current places of residence.^[105]

Abbasids found themselves at odds with the Shia Muslims, most of whom had supported their war against the Umayyads, since the Abbasids and the Shias claimed legitimacy by their familial connection to Prophet Muhammad; once in power, the Abbasids had disavowed any support for Shia beliefs in favor of Sunni Islam. Shortly thereafter, Berber Kharijites set up an independent state in North Africa in 801. Within 50 years the Idrisids in the Maghreb and Aghlabids of Ifriqiya and a little later the Tulunids and Ikshidids of Misr were effectively independent in Africa. The Abbasid authority began to deteriorate during the reign of al-Radi when their Turkic Army generals, who already had de facto independence, stopped paying the Caliphate. Even provinces close to Baghdad began to seek local dynastic rule. Also, the Abbasids found themselves to often be at conflict with the Umayyads in Spain. The Abbasid financial position weakened as well, with tax revenues from the Sawād decreasing in the 9th and 10th centuries.^[106]

The Abbasid Caliphate differed from others in that it did not have the same borders and extent as Islam. Particularly, in the west of the Caliphate, there were multiple smaller caliphates that existed in relative peace with them.^[10] This list represents the succession of Islamic dynasties that emerged from the fractured Abbasid empire by their general geographic location. Dynasties often overlap, where a vassal emir revolted from and later conquered his lord. Gaps appear during periods of contest where the dominating power was unclear. Except for the Fatimid Caliphate in Egypt, recognizing a Shia succession through Ali, and the Andalusian Caliphates of the Umayyads and Almohads, every Muslim dynasty at least acknowledged the nominal suzerainty of the Abbasids as Caliph and Commander of the Faithful.

Centuries after the Abbasids' fall, several dynasties have claimed descent from them, as "claiming kinship relation with the Prophet Muhammad, that is, claiming an affiliation to the “People of the House” or the status of a sayyid or sharif, has arguably been the most widespread way in Muslim societies of supporting one's moral or material objectives with genealogical credentials."^[107] Such claims of continuity with Muhammad or his Hashemite kin such as the Abbasids foster a sense of "political viability" for a candidate dynasty, with the intention of "serving an internal audience" (or in other words, gaining legitimacy in the view of the masses).^[107] The final ruler of the Bahawalpur Indian princely state was particularly "fanciful about the ancestry he claimed. In Bahawalpur and Pakistan and the subcontinent, he was an Arab of the Abbasids and a conquror, a man drawing his wealth from the country but not part of it."^[108]

Among the most notable of these dynasties claiming Abbasid descent are the Wadai Empire which ruled parts of modern-day Sudan, the Bahawalpur (princely state) of India, and the Khanate of Bastak.^{[109][110][111]}

A common trope among Abbasid claimant dynasties is that they are descended from Abbasid princes of Baghdad, "dispersed" by the Mongol invasion in 1258 CE.^[108] These surviving princes would leave Baghdad for a safe haven not controlled by the Mongols, assimilate to their new societies, and their descendants would grow to establish their own dynasties with their Abbasid 'credentials' centuries later.^[112][113] This is highlighted by the origin myth of the Bastak khanate which relates that in 656 AH/1258 CE, the year of the fall of Baghdad, and following the sack of the city, a few surviving members of the Abbasid dynastic family led by the eldest amongst them, Ismail II son of Hamza son of Ahmed son of Mohamed migrated to Southern Iran, in the village of Khonj and later to Bastak where their khanate was established in the 17th century CE.^[8][115]

Meanwhile, the dynasty Wadai Empire relates a similar origin story from the Abbasids. The Wadais claimed descent from a man by the name of Salih ibn Abdullah ibn Abbas whose father Abdullah was an Abbasid prince who fled Baghdad for Hijaz upon the Mongol invasion. He had a son named Salih who would grow to become an "able jurist" and a "very devout man". The Muslim ulama on pilgrimage in Mecca met him and impressed by his knowledge, invited him to return with him to Sennar. Seeing the population's deviation from Islam, he "pushed further" until he found the Abu Sinun mountain in Wadai where he converted the local people to Islam and teachings them its ruling, after which they made him sultan thus beginning the foundations of the Wadai Empire.^[116]

With regards to the Bastak khanate, Shaikh Mohamed Khan Bastaki was the first Abbasid ruler of Bastak to hold the title of "Khan" after the local people accepted him as a ruler (Persian: خان, Arabic: الحاكم), meaning "ruler" or "king", a title which was reportedly bestowed upon him by Karim Khan Zand.^[117] The title then became that of all the subsequent Abbasid rulers of Bastak and Jahangiriyeh, and also collectively refers in plural form – i.e., "Khans" (Persian: خوانين) – to the descendants of Shaikh Mohamed Khan Bastaki. The last Abbasid ruler of Bastak and Jahangiriyeh was Mohamed A’zam Khan Baniabbassian son of Mohamed Reza Khan "Satvat al-Mamalek" Baniabbasi. He authored the book Tarikh-e Jahangiriyeh va Baniabbassian-e Bastak (1960),^[118] in which is recounted the history of the region and the Abbasid family that ruled it. Mohamed A’zam Khan Baniabbassian died in 1967, a year regarded as marking the end of the Abbasid reign in Bastak.