Otto I (c. 1128 -- July 8, 1184) was the second Margrave of Brandenburg, from 1170 until his death. Otto I was born into the House of Ascania as the eldest son of Albert I (``Albert the Bear''), who founded the Margraviate of Brandenburg in 1157, and his wife Sophie of Winzenburg. He had three sisters and six brothers, the best known of whom were Prince-Archbishop Siegfried of Bremen, and Count Bernhard of Anhalt, later Duke of Saxony.
Siegfried of Bremen
Count Bernhard of Anhalt