What is "yakun"

Yakun or Jakun, deriving from Old Norse Hákon, was a Varangian ( Viking) leader who is mentioned in the Primary Chronicle and in the Cave monastery in Kiev. The chronicle tells that he arrived in Kievan Rus' in the year 1024 and fought in the Battle of Listven between the half-brothers Yaroslav I the Wise and Mstislav of Chernigov.