Background
His mother had been previously married and widowed, after which she entered a convent.
His mother had been previously married and widowed, after which she entered a convent.
Thankmar"s legitimacy was, therefore, in question. In 929, Henry I arranged for his succession and had the arrangement ratified by an assembly at Erfurt, just before his death. Otto, however, was designated by his father to receive the crown.
The only succession dispute was between Otto and his younger full brother Henry, who was kept under house arrest in Bavaria during Otto"s coronation.
After the death of Siegfried, Count of Merseburg in 937, Thankmar claimed Merseburg. Otto, however, appointed Gero, Siegfried"s brother.
During this dispute, Eberhard of Franconia and Wichmann the Elder revolted against Otto and Thankmar joined them. Later, Thankmar was besieged in Eresburg.
He was killed by a spear thrown through the window of the church of Saint Peter, while he was seeking refuge inside.