 At about the time of Samo's realm, the Kubrat of the Dulo clan led a successful uprising to end Avar authority over the Pannonian Plain; he established Old Great Bulgaria, or Patria Onoguria, "the homeland of Onogurs".The civil war, possibly a succession struggle in Onoguria between the joint Kutrigur and Utigur forces, raged from 631 to 632.The power of the Avars' Kutrigur forces was shattered and the Avars came under the control of Great Bulgaria.