In 965, Gero the Great, an uncle, if the onomastics hold true, died and his great march, the marca Geronis, was divided into five smaller marches. Odo received the so-called marca Orientalis or Eastern March.1 Odo was also later granted the countship of the gau of Nizizi. Odo first appeared with the title marchio (margrave) only in 974, though he had held marcher territories (officially as a county) since 965. In that same year (974), Odo was made Count of Nordthüringau.
Odo made war on Mieszko I of Poland, but the Emperor Otto I, from his seat at far off Mezzogiorno, ordered him and Mieszko to cease until he himself could arbitrate their dispute.2Thietmar of Merseburg, apparently quite gladly, relates that Odo's reputation with Mieszko was such that the duke of Poland "would not have dared while wearing his fur coat to enter a house where he knew the margrave to be, or to remain seated when the margrave stood up."3 In 979 (or 972), Odo, intending to compel Mieszko to pay tribute for the territory between the Oder and the Warthe, invaded that region, but was defeated on 24 June979 (or 972) at the Battle of Cedynia.4
Odo left a son, Siegfried, who became a monk at Nienburg, but left the monastery on his father's death to claim his inheritance. In this he failed, though he was a count in 1018 and he allied with Mieszko II of Poland in 1030.
Sources
Reuter, Timothy. Germany in the Early Middle Ages 800–1056. New York: Longman, 1991.
Thompson, James Westfall. Feudal Germany, Volume II. New York: Frederick Ungar Publishing Co., 1928.