Ahom–Mughal conflicts refer to the period between the first Mughal attack on the Ahom kingdom in 1615 and the final Battle of Itakhuli in 1682. The intervening period saw the fluctuating fortunes of both powers and the end of the rule of Koch Hajo. It ended with the Ahom influence extended to the Manas river which remained the western boundary of the kingdom till the advent of the British in 1826.

The Ahoms are said to be migrated in the 13th century, to the valley of the Brahmaputra from present-day Myanmar. The Ahoms created a new state by suppressing the older political system of the bhuiyans i.e. landlord and occupying the kingdoms of the Chhutiyas in 1523 and Koch-Hajo in 1581 – all during the 16th Century. The Ahoms built a large state and ruled the region for more than 600 years till it was annexed by the British. From the beginning the relationship between the Ahoms and the Mughals was hostile and that was due to certain factors, such as, Mughal alliance with Koch Bihar, the western enemy of the Ahoms and secondly the growing advance of the Mughals in north-eastern frontier which alarmed them. While the Mughals supported Lakshminarayan, son of Nara Narayan of Koch Behar, the Ahom king Sukhaamphaa (1552–1603) entered into alliance by marrying the daughter of Lakshminarayan's cousin Raghudeva, the son of Chilarai who became the ruler of the eastern part of the kingdom, Koch Hajo which included the modern districts of Goalpara, Barpeta, Kamrup, Darrang and a part of Sonitpur (up to Bharali). This dynastic alliance between Ahom and Koch was renewed afterwards by the next Ahom king Susenghphaa (Pratap Singha, 1603-1641) who married a daughter of Raja Parikshit. It is true that with a view to satisfy the territorial ambitions of his own nephew, Nar Narayan allowed partition of his kingdom. But unfortunately, in spite of being pacified, Raghudeva and his successors remained all along hostile towards the Koch royal house and this rivalry and antagonism between these two frontier states invited intervention and aggression of their two mighty neighbourhood powers: the Mughals on the west and Ahoms on the east.

From the time the Mughals appeared in the north-eastern frontier, a state of indirect rivalry and hostility began between the Mughals and the Ahoms. After the final defeat of Parikshit (1613) the first organised Mughal attack upon Assam was made with a view to conquer that kingdom. It was the outcome of the aggressive imperialism of the Mughals. "A desire for political supremacy and territorial expansion appears to have been the guiding motives of the Mughals." Boundary disputes and the trade rivalries appear to have complicated the situation and political issues precipitated the conflict. After the extinction of the Kamrup monarchy, the Mughals came to regard the territory east of Barnadi up to Singiri as part of the conquered region and hence asserted their political right over it. Ahoms strongly resented this claim. "Moreover the rich natural resources of the Assam valley and the prosperous kingdom of Kamrup in lower Brahmaputra valley, abounding in elephants and aromatic plants excited the cupidity of the Mughals and they were determined to force open the door of Assam."^[1]

The first organised open encounter with the Ahom kingdom was the well-deserved punishment meted out by the Ahom government to an unauthorised trader from Mughal India named Ratan Singh. His illicit trade was detected, his goods were confiscated and he was expelled from Assam. The Mughals got the necessary pretext for war and an imperial army was at once detached in 1615 under the command of Abu Bakr and Raja Satrajit of Bhusna. The imperial army advanced towards Barnagar, the old capital of Kamrup and next moved to Hajo and numerous outposts were raised in the surrounding region. In November 1615, Abu Bakr suddenly fell upon Kajali, the Ahom frontier post on the southwest. After a short skirmish, the Ahoms were defeated and leaving their war boats and the fort, they fled. Flushed with easy success the Mughals indulged in a series of aggressive measures against the Ahoms. The Ahom king then fortified the fort of Samdhara with a view to check the advance of the Mughals. Meanwhile, the Mughals had reached the confluence of the Brahmaputra and the Bharali facing Samdhara. After a month of inaction, the Mughals achieved a great triumph. They transported their horses across the Bharali and made a violent assault on the Ahom stockade on the left bank. The Ahoms thus suffered another discomfiture. The Ahom king sent a strong detachment to the Ahom commanders at Samdhara and exhorted them to fall on the enemy and fight to finish. The Ahoms gained an initial success and reoccupied the stockade at the mouth of Bharali. The imperialists were taken by complete surprise and suffered heavy casualties. Thus in spite of the initial success, the maiden attempt of the Mughals upon Assam ended in a disastrous failure. They suffered a colossal loss in men and money besides military prestige.^[2]

After the first disastrous failure in Assam, the Mughals henceforth continued to follow a defensive and conciliatory policy in regards to the Assam state. Because of their heavy engagement in Kamrup, the Mughals henceforward were very cautious not to offend their mighty neighbour. But the Ahoms being encouraged at their recent brilliant success continued to pursue hostile policy against the Mughals and proceeded to take advantage of the prevailing political confusion in Kamrup. The Assam disaster encouraged seditions and rebellions in Mughal occupied Kamrup. The Ahoms encouraged the Kamrup rebels and thereby caused hardship to the Mughals. There was hardly any open and direct conflict between the two powers as such. In the year 1618 CE the Ahom king Pratap Singha installed Balinarayan, the brother of Parikshit as King of Darrang and continued to help him for some time to reoccupy Kamrup. But in spite of Ahom king's material assistance, Balinarayan ultimately failed to reconquer Kamrup. The Ahoms interfered in Kamrup for the third time on behalf of the hill chiefs of Dhanikal in 1619. The hill chiefs being sick of Mughal subjection made a bold attempt to seize the hill fort of Ranihat and they sought the help of the Ahom king. The Ahom responded to the appeal and sent a large detachment to their assistance. After hard fighting, the Mughals courted defeat and were compelled to evacuate Ranihat hotly pursued by the Ahoms. But the Mughals soon gathered strength and recovered Dhanikal in spite of the stiff resistance of the Ahoms. Thus three attempts of the Ahoms at supplanting Mughal authority in Kamrup proved abortive. The Ahom king gradually withdrew from the arena of Kamrup policies leaving Balinarayan to his fate.

The reign of Shah Jahan (1628–1655) marks a new epoch in Ahom-Mughal relations. After a decade of informal hostility, circumstances paved the way for the renewal of open conflict between the two powers. Twofold factors, both political, appear to have been responsible for the conflict. The first was the asylum given by the Ahom king to the hill-chiefs of Dhanikal who had sought his protection against the ill-treatment of the Bengal Subahdar Qasim Khan Chishti. The second factor, which precipitated the crisis, was the wickedness and treachery of Satrajit, the Thanadar of Pandu who made a common cause with Balinarayan and instigated him to take advantage of the change of governor in Bengal in order to attack Kamrup. The invasion of Kamrup by Balinarayan compelled the Mughals to resort to arms. The Ahoms gained initial success. A fierce encounter took place, which ultimately ended with the total discomfiture of the imperialists. Thereupon, the Mughal fell back to their frontier post of Hajo. The Ahoms laid siege to Hajo and fighting continued for some time. At last both sides having been thoroughly worn out, the fighting was stopped for some time.^[3]

The Ahom-Mughal conflict started afresh towards the end of December 1636. The Mughals entered Kamrup proper. The decisive defeat inflicted by the imperialists on Balinarayan and the Ahoms in November 1637 turned the tide of fortune in favour of imperialists. The whole of Kamrup was cleared and re-annexed to the Pan-Mughalia. The third round of conflict began soon. The imperialists advanced up the Brahmaputra and halted opposite to Samdhara in October 1638; severe fighting ensued. Although the faint-hearted Ahom admiral retired from battlefield, the garrison in the fort of Samdhara offered such a gallant defence that the Mughals had to give up the contest with great loss of men and materials.^[3]

Both sides became eager for peace. Hence a treaty of peace was signed in February 1639. According to the Treaty of Asurar Ali between the Ahom general Momai Tamuli Borbarua, and the Mughal commander Allah Yar Khan, western Assam commencing from Gauhati passed into the hands of Mughals.^[4] The Ahom king, for the first time, acknowledged formally the Mughal overlordship in Kamrup, the Mughals acknowledged the independence of the Ahom king and gave up all pretensions to the territories east of Barnadi on the north and Kalang on the south and the Ahom king agreed not to interfere in Kamrup. Besides trade and commercial intercourses were resumed.^[5][6]

The Ahom-Mughal relation following the peace of 1639 was far from satisfactory. However, it would be wrong to assume that both sides strictly honoured the peace treaty of 1639. The keynote of the political history of this period is the endless criminations and recriminations of the Mughals and the Assamese on various rounds, such as, 'Kheda' operations, trade and commercial intercourse, boundary disputes, extradition of political offenders, and violation of personal liberty and privileges of the subject people. On these issues frictions continued mounting without, of course, any open armed-clash. It was really a period of armed peace between the Mughals and the Ahoms.

In 1648, the Mughal Faujdar of Gauhati sent a message of congratulations to the Ahom king Jayadhwaj (Sutamla) on his succession. But, Jayadhwaj Singha (1648–1663), taking advantage of the emperor Shah Jahan's illness and the war of succession, expelled the Mughals from Gauhati, and chased them down beyond the river Manaha (Manas). He also devastated the territory near Dacca and carried off to Assam a large number of Mughal subjects as captives.^[7][8]

Aurangzeb after ascending on the throne of Delhi ordered Mir Jumla to invade Cooch Behar and Assam and re-establish Mughal prestige in eastern India. After having occupied Koch Behar had also declared its independence. Mir Jumla entered Assam in the beginning of 1662. He easily repulsed the feeble resistance offered by the Assamese at the garrisons between Manaha and Guwahati. He occupied one garrison after another, and Pandu, Guwahati, and Kajali fell into the hands of the Mughals practically unopposed.

The easy success of Mir Jumla was due to dissatisfaction in the Assam camp. The leading commanders and the officers were the exclusive monopolies of the Tai-Ahom. But. King Jayadhwaj Singha had appointed a Kayastha as viceroy of Western Assam and commander-in-chief of the Ahom army despatch against Mir Jumla leading to resentment among the ranks. This officer was Manthir Bharali Barua of Bejdoloi family. He was also appointed Parbatia Phukan. This appointment caused bitter resentment among the hereditary Ahom nobles and commanders and the resistance which they offered to the invaders was neither worthy of the efficient military organisation of the Ahoms nor of the reputation which they acquired by repeated success in their enterprises against foreigners, and Mir Jumla's march into Assam was an uninterrupted series of triumph and victories through the real secret of his success, namely, defection in Ahom camp, which has not been touched upon by any historian of the expedition.

The Ahoms, however, recovered their senses when the hostile force reached the neighbourhood of Kaliabor. They concentrated their defence at Simalugarh and Samdhara. In February 1662, Mir Jumla laid siege to Simalugarh and after the severe hand-to-hand fight, the Ahoms abandoned the fort and took to flight. The Ahom forces at Samdhara on the opposite bank, being unnerved by the fall of Simalugarh, left their charge without any opposition worth the name. After this brilliant success, Mir Jumla entered the Ahom capital Garhgaon on 17 March 1662. The Ahom king Jayadhwaj took shelter in the eastern hills abandoning his capital and all his treasures. Immense spoils fell into the hands of the Mughal Empire – 82 elephants, about 300,000 coins in gold and silver, 675 big guns, about 4750 maunds of gunpowder in boxes, 7828 shields, 1000 odd ships, and 173 stores of rice.

But, Mir Jumla conquered only the soil of Ahom capital and neither the king nor the country. The rainy season was fast approaching and so Mir Jumla halted there and made necessary arrangements for holding the conquered land. Communications with the imperial fleet at Lakhau as well as with Dacca were arranged. But the torrential rain and violence of the rivers caused immense hardship to the Mughals and the communication with the Mughal fleet and Lakhau and with Dacca became completely disrupted.

The Ahoms took the fullest advantage of the unspeakable hardship of the Mughals. With the progress of monsoon, the Ahoms easily recovered all the country east of Lakhau. Only Garhgaon and Mathurapur remained in the possession of Mughals. The Ahoms were not slow to take advantages of the miserable plight of the Mughals. The Ahom king came out of his refuge and ordered his commanders to expel the invaders from his kingdom. A serious epidemic broke out in the Mughal camp at Mathurapur, which took away the lives of hundreds of Mughal soldiers. There was no suitable diet or comfort in the Mughal camp. At last life became unbearable at Mathurapur and hence the Mughals abandoned it.^[9]

By the end of September, the worst was over. The rains decreased, and flood went down, roads reappeared and communications became easier. The contact with the Mughal fleet at Lakhau was restored which cheered the long-suffering Mughal garrison. The Mughal army under Mir Jumla joined the fleet at Devalgaon. The Ahom king Jayadhwaj Singha took refuge in hill again. But in December, Mir Jumla fell seriously ill and the soldiers refused to advance any further. Meanwhile, the Ahom king became extremely anxious for peace. At last a treaty was concluded at Ghilajharighat in January 1663, according to which the Ahoms ceded western Assam to the Mughals, promised a war indemnity of three lakhs of rupees and ninety elephants. Besides, the king had to deliver his only child and daughter Ramani Gabharu, as well as his niece, the daughter of the Tipam Raja to the harem of the Mughal emperor. Thus, according to the treaty Jayadhwaj Singha transferred Kamrup to the possession of the Mughals and promised to pay a heavy war indemnity.^[10][11]

The question of prompt payment of war indemnity of elephants and cash became a source of friction between the Ahoms and the Mughals. The first installment was paid by Jayadhwaj promptly. But as soon as Mir Jumla withdrew from Assam the Ahoms began to default. Jayadhwaj Singha's successor Chakradhwaj Singha (Supangmung, 1663-1670) was against any payment at all on principle. He shouted out from his throne: – "Death is preferable to a life of subordination to foreigners". In 1665 the king summoned an assembly of his ministers and nobles and ordered them to adopt measures for expelling the Mughals from western Assam, adding—"My ancestors were never subordinate to any other people; and I for myself cannot remain under the vassalage of any foreign power. I am a descendant of the Heavenly King and how can I pay tribute to the wretched foreigners."^[12][13]

A large portion of the war indemnity still remained undelivered for which the Ahom king had to receive threatening letters from Syed Firoz Khan, the new Faujdar at Guwahati.^{[14][15][16][17]} On receiving Firoz Khan's letter the Ahom king made up his mind to fight.^[18] On Thursday, Bhadra 3, 1589 saka near aboutAugust 20, 1667, the Ahom army started from the capital and sailed down the Brahmaputra in two divisions. They encamped at Kaliabor, the Vice Regal headquarters, from where they conducted their war operations against the Mughals. Syed Firoz Khan, the imperial governor of Guwahati and his army were not prepared for such an eventuality, with the result that the Ahoms gained a series of victories over the enemy. The Ahom army on the south bank was successful in their fighting. Their chief objective was the capture of Itakhuli which is a small hill on the south bank of the Brahmaputra at Guwahati. On 2 November 1667, Itakhuli and the contiguous garrison of Guwahati fell into the hands of the Ahoms. The enemy was chased down to the mouth of the Manaha river, the old boundary between Assam and Mughal India. The Ahom also succeeded in bringing back the Assamese subjects who had previously been taken as captives by the Mughals during the expedition of Mir Jumla.^[19][20] Thus within the short span of two months the Ahoms succeeded their lost possession and along with it their lost prestige and glory, this was due to the determination and courage of Ahom king Chakradhwaj Singha. On receiving the news of victory the king cried out-"It is now that I can eat my morsel of food with ease and pleasure". The success of the Ahoms in recovering possession of Guwahati and western Assam forms a momentous chapter in the history of their conflicts with the Mughals.

In December 1667, the Mughal emperor Aurangzeb received intelligence of the capture of Guwahati by the Ahoms, and he at once resolved to dispatch a strong army to reestablish Mughal prestige in North-East frontier. He commissioned Raja Ramsingh I of Amber, son of the distinguished general Mirza-Raja Jai Singh I, to lead an invasion of Assam. He was accompanied by Rashid Khan, the ex-Faujdar of Guwahati. Ram Singha reached the frontier garrison of Rangamati in February 1669. On Ram Singha's arrival at Rangamati, the Ahom commanders stationed at Manaha attempted to oppose the advance of the enemy. There were few skirmishes, but the Assamese could not attain any success.^[21] The Assamese were not prepared for such an eventuality and they left their frontier garrisons and sailed down to Guwahati.

Also, the Ahoms had not quite completed their preparations for resisting Ramsingh I’s advance. Lachit Borphukan, the commander-in-chief of the Ahom camp had realized fully that postponement of the open encounter would enable him to bring his preparations to perfection in the light of the enemy’s superior strength. Lachit Borphukan sent the following message to Ram Singh "Tell Raja Ram Singh that we want to know why he has come to our country." Firoz Khan, ex-Fauzadar of Guwahatii, now a prisoner of the Ahoms, was released and Lachit Barphukan sent him to Raja Ram Singh with the above message.^[22][23][24] Ram Singh demanded through Firoz Khan the restoration of the limit fixed in 1639 between Allah Yar Khan and Momai Tamuli Borbarua. By the time he received this reply Barphukan would rather fight than yield an inch of the territory which providence had given to his master.^[25][26]

The result was that in the first two battles of the campaign were fought near Tezpur in the beginning of April 1669. The Ahoms were worsted on both occasions, but they gained a naval battle, and soon afterwards repulsed the Muhammadans and Ram Singha was compelled to retire to Hajo where he quarreled with Rashid Khan. Eventually, Ram Singha cut his tent ropes and ordered him out of the camp.^[27] Soon afterwards the Muhammadans were again defeated near Sualkuchi, both on land and water.

At this juncture, Ramsingh I challenged Chakradhwaj Singha to single combat, and undertook, if he were defeated, to return with the army to Bengal. The Ahom king declined the invitation, and ordered his generals to renew their attack. They did so, and won another double engagement near Sessa. They followed up this success by taking the fort at Agiathuti, but soon afterwards Ram Singha attacked the Ahom army and routed it, inflicting heavy loss. The Barphukan hurried up with reinforcements, but his flank was tired and he was obliged to retreat with loss of his ships. Raja Ram Singha now opened negotiations for peace. The Ahoms were also tired of the war, and hostilities were suspended for a time.^[27] Sporadic engagement accompanied by proposals of peace continued during 1669 and 1670. From October 1669 to March 1670, Ram Singha withdrew himself from the fight.^[28][29]

In the meantime Ramsingh I sent a letter to the Barphukan inviting the king of Assam to fight a duel in the presence of the two hostile armies. But the Ahom king dismissed the insolent challenge by simply saying—"Ram Singha is a mere servant and he has no umbrella over his head. So I do not like to fight a duel with such a man."^[30][31] Chakradhvaj Singha could not hold his patience any longer. In the meantime, the Mughal had then concentrated their army near Alaboi Hill in the vicinity of Dalibari. A terrible contest ensued on the plains to the south of the Alaboi Hill. The Ahoms were badly defeated in that battle. The massacre at Alaboi had terribly upset Lachit Barphukan. Though the Alaboi massacre meant a serious loss to the Ahoms, it did not confer upon the enemy any decisive advantage.^[32]

But Ram Singha repeated his demands for the evacuation of Guwahati and reversion to the status quo ante of the year 1639. The Barphukan remained firm in the position he had previously maintained. So war was inevitable between the two parties. But when the war was taking a more critical turn, Chakradhwaj Singha, the king of Assam died in April 1670. He was succeeded by his brother Udayaditya Singha (Sunyatphaa, 1670-1672)

Although the negotiations with the Mughals continued, but Ram Singha suspecting the sincerity of the Barphukan returned to attack. Udayaditya renewed the war and ordered the Barphukan to march with 20,000 men from Samdhara to Saraighat. The Ahoms were successful on land but their navy was forced to retreat. Barphukan arrived with more ships and Mughal army was beaten and the Ahoms also gained a second land victory. The Mughals could not stand the dash and fury of the Assamese onset. The Assamese were fighting for their life and liberty, and the Mughals for the mere luxury of triumph and territorial expansion. The Barphukan intended to chase them further still, but he was dissuaded by Achyutanda Doloi. The combat came to an end, and it was a decisive victory for the Assamese.^[33][34] This battle is known in history as the Battle of Saraighat. Ram Singha weakened by the repeated losses retreated to Rangamati in March 1671. Hadira opposite to Goalpara became the Ahom frontier outpost. Thus Mughals were evicted from Kamrup, strong fortifications were constructed at Guwahati. Thus Ahoms remained in undisturbed possession of their territories till 1679 A.D.^[35]

In 1679, during the reign of Sudoiphaa or Parvatiya Raja,^[36] Laluk Barphukan, the Ahom viceroy of Gauhati, and his brother entered into a conspiracy and invited the Nawab of Bengal to take possession of the fort at Saraighat.^[37] Accordingly, in March Laluk Sola made over Gauhati to the Mughals in return for a promised reward of four lakhs of rupees and an assurance to support Laluk's candidature for the throne of Assam.^[38]

In 1681, Gadapani was formally installed as sovereign of Assam under the name Gadadhar Singha (Supaatphaa, 1681-1696). His first act after taking reign was the dispatch of an army against Mansur Khan, which succeeded in recovering Gauhati in August 1682 after a decisive encounter at Itakhuli. The Ahoms expelled Mansur Khan from Gauhati and re-established their possession over the territories extending up to the river Manaha (Manas). Thus, Manaha (river Manas) became once more the western boundary of Assam and it remained as such till the occupation of the western Assam by the British in the year 1824.