The Franks probably developed out of various war-bands on the lower Rhine in the early 3rd century AD, coming to Roman attention particularly as sea raiders.
From the late 3rd century some Franks settled in Roman lands west of the Rhine. Warrior burials, often richly furnished, and female graves with similar material attest their growing presence as federate troops protecting Roman estates by the late 4th century.
By the later 5th century, the Franks had founded several petty kingdoms, still technically in treaty relation with the surviving pockets of the Roman Empire. One of these was ruled by Childeric, father of Clovis who welded the Franks into a single kingdom.
Starting with northern Gaul, Clovis defeated all his neighbours (Visigoths, Burgundians, Thuringians and Alamanni) to become master of Gaul. Baptized a Christian in 496 or 499, Clovis, a shrewd and cunning strategist, thus won the support of the Catholic Roman clergy and could cloak his territorial expansion in the guise of a Holy War against the pagans or the heretical followers of rival Christian sects, who were infinitely worse in Catholic eyes.
Clovis had a fine apologist in Gregory of Tours, a bishop who wrote a partisan 'History of the Franks' at this time.
