Initially, Prokop was a member of the Utraquists (the moderate wing of the Hussites) and was a married priest (having received the tonsure early in life) who belonged to an eminent family from Prague. He studied in Prague, and then traveled for several years in foreign countries. On his return to Bohemia, though a priest and continuing to officiate as such, he became the most prominent leader of the advanced Hussite or Taborite forces during the latter part of the Hussite Wars. He was not the immediate successor of Jan Žižka as leader of the Taborites, as has been frequently stated, but he commanded the forces of Tabor when they obtained their great victories over the Germans and Catholics at Ústí nad Labem in 1426 and Domažlice in 1431. The crushing defeat that he inflicted on the crusaders of the Holy Roman Empire at Domažlice led to peace negotiations (1432) at Cheb between the Hussites and representatives of the Council of Basel.