Otto III, called the White and known as Otto of Schweinfurt, was the margrave of the Nordgau (1024–1031) and duke of Swabia (1048–1057). He was the son of Henry of Schweinfurt, margrave of the Nordgau, and Gerberga of Henneberg. Otto was one of the most powerful East Franconian princes by inheritance: having extensive land in the Radenzgau and Schweinfurt. In 1014, he first appears as count of Lower Altmühl and, in 1024, he inherits his father's march. In 1034, Otto became count of the Lower Naab. From then on to his appointment to Swabia, he takes part in many imperial expeditions into Bohemia, Hungary, and Poland. He was betrothed to Matilda, daughter of Bolesław I the Brave, but the arrangement fell through.