As Roman power waned through the first half of the fifth century CE large areas of Western Europe were settled by Germanic peoples. These were late migrants from the east, in some cases from the Indo-European heartland northwest of the Black Sea. The earlier Celtic-speaking peoples who had occupied the region for a millennium were gradually displaced, their territory largely confined to the British Isles. Following the sacking of Rome in 476, the Germanic Ostrogoths gained control over most of Italy. A power vacuum developed across Northern Europe; petty kingdoms sprang up among people linguistically and ethnically related, each vying for territorial control. In France the Burgundians controlled the southeast from Lyon and Geneva while the Visigoths set up a kingdom at Toulouse. Tours became a center of Frankish power, but it is clear from the writings of Gregory, bishop of Tours (573–594 CE), that the common culture of these numerous tribes was a remnant Christian culture left over from Roman times.

Gregory's indispensable contribution was his compilation known as Historia Francorum (The History of the Franks) completed in 594 CE, which was originally presented in ten books, Decem Libri Historiarum (Ten Books of History). Gregory was well placed to write this history; he himself was responsible for eight sees extending west into Brittany (Gregory of Tours 2010, 10–13). Historians have judged Books 5 to 10 as reliable in their presentation of his own time, the late sixth century; as one remarks, Gregory has become “a byword for credibility as scholars seek but rarely find factual error in those things which Gregory knew best” (Gerberding 1987, 2). Through Books 2 to 4, which cover the years from 397 to 575, he relied on a variety of earlier writers, including Eusebius, Jerome, and Orosius, and his usage reveals an early example of careful use of sources (2010, 27–28). However, Gregory cast the whole into a larger framework with an extended background rooted in the Bible. As such, the Historia Francorum presents the first version of a post-Roman legendary empire that will continue to develop through the next six hundred years.

The first book of Gregory's history includes a paraphrase of the Bible, a history of Roman persecution, and the bishopric of Tours up to the death of its third bishop, St. Martin, in the year 397 CE.