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. <sep>, Pronoun: He <sep>, A: Siegfried of Bremen <sep>, B: Count Bernhard of Anhalt