Osbeorn Bulax's father governed on what king's behalf?
Osbeorn Bulax Osbeorn (died c. 1054), given the nickname Bulax, was the son of Siward, Earl of Northumbria (died 1055). He is one of two known sons — probably the older — of Siward. While it is normally assumed he was the son of Siward's Bamburgh wife Ælfflæd, it has been suggested by William Kapelle that Osbeorn's mother was not Ælfflæd. The nickname "Bulax" probably represents the Old Norse term for "Poleaxe".
Tudun A tudun was a governor resident in a town or other settlement in the ancient Bulgar, Avar or Gokturk empires, particularly those of the Bulgars and the Khazars . In Gothic, "þiudans" means "king" (literally "leader of the people", hence "prince, lord, ruler, chief"). The tudun was the personal representative of the imperial government and could function both as an administrator and a diplomat. At times, a tudun would be appointed for a town nominally under another power's control but "de facto" within the sphere of influence of the tudun's khagan.