Frederick set out on 11 May 1189 with an army of 12,000–15,000 men, including 2,000–4,000 knights. Contemporary chroniclers gave a range of estimates for Frederick's army, from 10,000 to 600,000 men, including 4,000–20,000 knights. After leaving Germany, Frederick's army was increased by the addition of a contingent of 2,000 men led by the Hungarian prince Géza, the younger brother of the king Béla III of Hungary, and Bishop Ugrin Csák. Two contingents from the Empire, a Burgundian and a Lorrainer, also joined the army during its transit of Byzantium. The army that Frederick led into Muslim territory was probably larger than the one with which he had left Germany.