Clovis united the Franks and helped solidify them as the dominant power in northwestern Europe after the collapse of the Roman Empire. He created the first Kingdom of France and also helped built out what would becomes Charlemagne's Empire.
Bernard Bachrach, Merovingian Military Organization, 1972
Ralph Mathison, Clovis, Anastasius, and Political Status in 508 CE, 2012
Charles Oman, The Dark Ages, 476-918, 1898
Ian Wood, The Merovingian Kingdoms 450-751, 1994