The oldest known member of the House of Wettin was Thiedericus (died 982). Around 1000, as part of the German conquest of Slavic territory, the family got Wettin Castle and changed their name. It was usual for noblemen to change their name to the name of their territory. Wettin Castle is located in Wettin, Saxony-Anhalt in the Hosgau on the Saale River. 