Louis the Child (893 – 20/24 September 911), sometimes called Louis III or Louis IV, was the king of East Francia from 900 until his death in 911 and was the last ruler of the Carolingian dynasty there. He succeeded his father, king Arnulf of Carinthia in 899, when he was six. Louis also inherited the crown of Lotharingia with the death of his elder illegitimate half-brother Zwentibold in 900. During his reign the country was ravaged by Magyar raids.

Louis was born in September or October 893 in Altötting, Duchy of Bavaria. He was the only legitimate son of king Arnulf of Carinthia and his wife, Ota, a member of the Conradine dynasty. He had at least two brothers: his elder, illegitimate brother Zwentibold, who ruled Lotharingia, and another brother named Ratold, who briefly ruled Kingdom of Italy. Ratold's maternity and age are unknown.

Louis was crowned in Forchheim on 4 February 900.^[1] This is the earliest East Frankish royal coronation about which records are known to exist. Louis was of a weak personal constitution, often sick, and due to his young age, the reins of government were entirely in the hands of others - the nobles and bishops. Indeed, the coronation was probably a result of the fact that there was little Louis could gain at the expense of the nobles.

The most influential of Louis's councillors were Hatto I, and Solomon III (bishop of Constance). It was these two who assured that the royal court decided in favour of the Conradines against the Babenbergers in the matter of the Duchy of Franconia. They appointed Louis's nephew, Conrad as a duke. In 903 Louis promulgated the Raffelstetten Customs Regulations, the first customs regulations in the East Frankish part of Europe.

In 900, during Hungarian invasions of Europe, Magyar army ravaged Bavaria. Another group of Magyars were defeated by Luitpold, Margrave of Bavaria and Bishop Richer of Passau. In 901 they devastated the Duchy of Carinthia. In 904 Louis invited Kurszán, the kende of Magyars to negotiations, but killed him and his delegation.^[2][3] In 906 Magyars twice ravaged Duchy of Saxony. In 907 they inflicted a heavy defeat on the Bavarians who had invaded Hungary, killing the Margrave Liutpold and many high nobles in the Battle of Pressburg. Next year it was the turn of Saxony and Thuringia, in 909 that of Alemannia. On their return, however, Arnulf, Duke of Bavaria inflicted a defeat on them on the river Rott, but in 910 they, in their turn, defeated Louis the Child's army in the Battle of Augsburg.^[4] Louis himself tried to take some military control as he grew older, but he had little success against the Magyars. His army was destroyed at Ennsburg in 907.

In a state of despair, possibly afflicted by severe depression, Louis died at Frankfurt am Main on 20 or 24 September 911, seventeen or eighteen years old. Louis was buried in the monastery of Saint Emmeram in Regensburg, where his father Arnulf of Carinthia lay. His death brought an end to the eastern (German) branch of the Carolingian dynasty.

The vacuum left in the Carolingian East was eventually filled in 919 by the family of Henry the Fowler, a cousin, and heralded the beginning of the Ottonian dynasty. However, in 911 the dukes of East Francia elected Conrad of Franconia as the king of East Francia, while the nobles of Lotharingia elected as their king Charles the Simple, king of West Francia.

In an interview with the Daily Trojan, one member of the EDM duo Louis the Child said, "We went on Wikipedia and hit the random article button a couple of times, then Louis The Child popped up and we thought, 'Yeah, that sounds good and we went with it.'"^[5]