 In the 630s, Samo, the ruler of the first historically known Slavic polity known as Samo's Tribal Union or Samo's realm, increased his authority over lands to the north and west of the Khaganate at the expense of the Avars, ruling until his death in 658.The "Chronicle of Fredegar" recorded that during Samo's rebellion in 631AD, 9,000 Bulgars led by Alciocus left Pannonia to modern-day Bavaria where Dagobert I massacred most of them.The remaining 700 joined the Wends.