1000; died 10 January 1030) was the Count of the Schwabengau and Nordthüringgau from 1010 and the Margrave of the Saxon Ostmark from 1015 until his death.
In 1028, the Ostmark, with the rest of the eastern marches of the Duchy of Saxony fell under attack from Mieszko II of Poland.
The Emperor Conrad II rushed from central Saxony and trekked over very wild terrain to besiege the Poles in Bautzen.
Conrad, however, failed to take Bautzen (1029) and returned to the Rhineland by wintertime, leaving the defences of the realm in the hands of Dietrich II of Wettin and Thietmar, who died early in January.
He left a daughter, Oda, who married William III of Weimar and then Dedo II of Wettin, who succeeded her brother Odo.