When Charibert and his son Chilperic were assassinated in 632, Dagobert had Burgundy and Aquitaine firmly under his rule, becoming the most powerful Merovingian king in many years and the most respected ruler in the West. In 631, Dagobert led a large army against Samo, the ruler of the Slavic Wends, partly at the request of the Germanic peoples living in the eastern territories and also due to Dagobert's quarrel with him about the Wends having robbed and killed a number of Frankish merchants. While Dagobert's Austrasian forces were defeated at the Wogastisburg, his Alemmanic and Lombard allies were successful in repelling the Wends. Taking advantage of the situation at the time, the Saxons offered to help Dagobert if he agreed to rescind the 500 cow yearly tribute to the Austrasians. Despite accepting this agreement, Fredegar reports that it was to little avail since the Wends attacked again the following year.