The most famous event of Samo's career was his victory over the Frankish royal army under Dagobert I in 631 or 632. Provoked to action by a "violent quarrel in the Pannonian kingdom of the Avars or Huns", Dagobert led three armies against the Wends, the largest being his own Austrasian army. The Franks were routed near Wogastisburg; the majority of the besieging armies were slaughtered, while the rest of the troops fled, leaving weapons and other equipment lying on the ground. In the aftermath of the Wendish victory, Samo invaded Frankish Thuringia several times and undertook looting raids there. Dervan, the "duke of the Sorbs" (""), initially subordinate to the Franks, joined the Slavic tribal union after Samo defeated Dagobert I. The Sorbs lived to the east of the Saxon Saale. Dervan participated in the subsequent wars against the Franks, successfully fighting against Frankish Thuringia (631–634), until he was finally defeated by Radulf of Thuringia in 636.