 He did not officially take the title Margrave of Brandenburg until his father's death in 1170, but as early as 1144 he is mentioned by that title along with Albert in a royal document, although Albert himself did not claim it until 1157.The father and son together shaped the House of Ascania's policy over several decades, together participating in meetings and decisions, and are both frequently mentioned in documents of the period.The pair were accompanied and supported in many cases by Otto's brothers, in particular the second-eldest, Hermann.