The Merovingian dynasty was the ruling family of the Franks from around the middle of the 5th century until 751. They first appear as "Kings of the Franks" in the Roman army of northern Gaul. By 509 they had united all the Franks and northern Gallo-Romans under their rule. They conquered most of Gaul, defeating the Visigoths (507) and the Burgundians (534), and also extended their rule into Raetia (537). In Germania, the Alemanni, Bavarii and Saxons accepted their lordship. The Merovingian realm was the largest and most powerful of the states of western Europe following the breaking up of the empire of Theodoric the Great.