Anawrahta
Banned
Childeric I and maybe his grandson ruled the Salian kingdom from Tournai as a Foederatus of the Romans. Childeric and his son Clovis, who received the kingdom from his father, began to extend his influence over other Frankish tribes and expanded further south and west into Gaul. Clovis became a Christian, legitimizing his rule over his Gallo-Roman subjects and thus gained the support of the Church. Frankia subsequently became the most powerful Western European state during the Dark Ages.
Later on more Northern peoples also converted to Christianity, so if you are going for a pagan state versus Christian expansion, it would be an uphill "fight".