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Origins

The term "Franks" emerged in the 3rd century AD as a term for several Germanic tribes who settled on the northern Rhine frontier of the Roman Empire, including the Bructeri, Ampsivarii, Chamavi, Chattuarii and Salians. While all of them had a tradition of participating in the Roman military, the Salians were allowed to settle within the Roman Empire. In 358, having already been living in the civitas of Batavia for some time, Emperor Julian defeated the Chamavi and Salians, allowing the latter to settle further away from the border, in Toxandria.

Some of the early Frankish leaders, such as Flavius Bauto and Arbogast, were committed to the cause of the Romans, but other Frankish rulers, such as Mallobaudes, were active on Roman soil for other reasons. After the fall of Arbogastes, his son Arigius succeeded in establishing a hereditary countship at Trier and after the fall of the usurper Constantine III some Franks supported the usurper Jovinus (411). Jovinus was dead by 413, but the Romans found it increasingly difficult to manage the Franks within their borders. The Frankish king Theudemer was executed by the sword, in c. 422.

Around 428, the king Chlodio, whose kingdom may have been in the civitas Tungrorum (with its capital in Tongeren), launched an attack on Roman territory and extended his realm as far as Camaracum (Cambrai) and the Somme. Though Sidonius Apollinaris relates that Flavius Aetius defeated a wedding party of his people (c. 431), this period marks the beginning of a situation that would endure for many centuries: the Germanic Franks ruled over an increasing number of Gallo-Roman subjects.

The Merovingians, reputed to be relatives of Chlodio, arose from within the Gallo-Roman military, with Childeric and his son Clovis being called "King of the Franks" in the Gallo-Roman military, even before having any Frankish territorial kingdom. Once Clovis defeated his Roman competitor for power in northern Gaul, Syagrius, he turned to the kings of the Franks to the north and east, as well as other post-Roman kingdoms already existing in Gaul: Visigoths, Burgundians, and Alemanni.

The original core territory of the Frankish kingdom later came to be known as Austrasia (the "eastern lands"), while the large Romanised Frankish kingdom in northern Gaul came to be known as Neustria.