Otto I of Brandenburg

Otto I (c. 1128–1184) was the second Margrave of Brandenburg, ruling from 1170 as the eldest son of Albert the Bear, who had founded the margraviate in 1157. Already active in his father's government by 1144, after 1157 the two shaped Ascanian policy together.

Around 1148 he married Judith, daughter of Polish duke Bolesław III. As margrave he focused on settling and securing the territory rather than expanding it, and was buried at Lehnin Abbey.