Osbeorn Bulax's father governed on what king's behalf?
Siward, Earl of Northumbria Siward or Sigurd ( or more recently ; Old English: "Sigeweard") was an important earl of 11th-century northern England. The Old Norse nickname "Digri" and its Latin translation "Grossus" ("the stout") are given to him by near-contemporary texts. Siward was probably of Scandinavian origin, perhaps a relative of Earl Ulf, and emerged as a powerful regional strongman in England during the reign of Cnut ("Canute the Great", 1016–1035). Cnut was a Scandinavian ruler who conquered England in the 1010s, and Siward was one of the many Scandinavians who came to England in the aftermath of that conquest. Siward subsequently rose to become sub-ruler of most of northern England. From 1033 at the latest Siward was in control of southern Northumbria, that is, present-day Yorkshire, governing as earl on Cnut's behalf.
Arses of Persia Artaxerxes (Artaxšacā) IV Arses (Persian: اردشيرچهارم‎ ‎ ) (Old Persian: ), was king of Persia between 338 BC and 336 BC. He was the youngest son of King Artaxerxes III and Atossa and was not expected to succeed to the throne of Persia. His unexpected rise to the throne came in 338 BC as a result of the murder of his father and most of his family by Bagoas, the powerful Vizier of Persia who had recently fallen into disfavor with Artaxerxes. Bagoas sought to remain in office by replacing Artaxerxes with his son Arses (Artaxerxes IV), whom he thought easier to control. Arses remained little more than a puppet-king during the two years of his reign, while Bagoas acted as the real power behind the throne. Eventually, disgruntled by this state of affairs and possibly influenced by the nobles of the Royal Court, who generally held Bagoas in contempt, Arses started planning Bagoas' murder. The Vizier again acted first in order to protect himself and managed to poison Arses. Bagoas then raised a cousin of Arses to the throne as King Darius III of Persia. A major concern for Persia during this King's short reign were hostilities on the western borders with Macedonia under Kings Philip II of Macedon and Alexander the Great. This became a war of conquest by Alexander during the reign of Arses' successor Darius III.