Until the
Treaty of Speyer, concluded on 23 May 1544, Adolf's half-brother
Christian III of Denmark ruled the entire Duchies of Holstein and Schleswig in the name of the then still minor Adolf and his brother
John the Elder (Hans den Ældre). They determined their youngest brother
Frederick was to have a career as Lutheran administrator. In 1551 Frederick became administrator of the
Prince-Bishopric of Hildesheim. In 1544, following negotiations between the elder three brothers and the nobility of the duchies, the brothers decided to partition the duchies of Holstein and Schleswig between themselves. The revenues of the duchies were divided into three equal shares by assigning the revenues of particular areas and
landed estates to each of the elder brothers. Other general revenues, such as taxes from towns and customs duties, were levied together and then shared among the brothers. The secular rule in the fiscally divided duchies was shared between the brothers. As dukes of Holstein and Schleswig the three brothers bore the formal title of "Duke of Schleswig, Holstein,
Ditmarsh and
Stormarn". Adolf founded a cadet branch of the royal Danish
House of Oldenburg called the
House of Holstein-Gottorp. John the Elder, the Duke of Schleswig-Holstein-Haderslev, produced no issue, so no branch emerged from his side. After his death in 1580, Adolf and his nephew
Frederick II of Denmark halved John's share among themselves. Adolf travelled, entrusting
Johan Rantzau to manage his country. Adolf participated in the
Diet of Augsburg where he witnessed Emperor
Charles V at the high point of his power. In 1553 Adolf returned to his homeland. In 1556 Adolf succeeded his younger brother Frederick as Bishop of Schleswig. ==Family and children==