The emperor Constantine I (d. 337) was important not only during his reign, but also in the following centuries when he was taken as a political role model by several Roman emperors and barbarian kings. This article looks at two of those barbarian kings: Clovis, king of the Franks at the end of the fifth and the beginning of the sixth century, and Reccared, king of the Visigoths (d. 601). Both of these kings converted to Catholicism, and both were compared with Constantine. This article analyses the meanings of these comparisons in the political, religious and ideological contexts of the Frank and Visigothic kingdoms.