that had accompanied the First Crusade and Second Crusade in Germany. Because Frederick had signed a treaty of friendship with Saladin in 1175, he felt it necessary to give Saladin notice of the termination of their alliance. On 26 May 1188, he sent Count Henry II of Dietz to present an ultimatum to Saladin. A few days after Christmas 1188, Frederick received Hungarian, Byzantine, Serbian and Seljuk envoys in Nuremberg. The Hungarians and Seljuks promised provisions and safe-conduct to the crusaders. The envoys of Stefan Nemanja, grand prince of Serbia, announced that their prince would receive Frederick in Niš. Only with difficulty was an agreement reached with the Byzantine envoy, John Kamateros. Frederick sent a large embassy ahead to make preparations in Byzantium. On 15 April 1189 in Haguenau, Frederick formally and symbolically accepted the staff and scrip of a pilgrim and set out. His crusade was "the most meticulously planned and organized" up to that time. According to one source written in the 1220s, Frederick organized a grand army of 100,000 men (including 20,000 knights) and set out on the overland route to the Holy Land; This number is believed to be inaccurate and modern estimates using contemporary sources place the size of his army at 12,000–15,000 men, including 3,000–4,000 knights. The Crusaders passed through Hungary, Serbia, and Bulgaria before entering Byzantine territory. Matters were complicated by a secret alliance between the Emperor of Constantinople, Isaac II Angelos, and Saladin, warning of which was supplied by a note from Sibylla, ex-Queen of Jerusalem. While in Hungary, Barbarossa personally asked the Hungarian Prince Géza, brother of King Béla III of Hungary, to join the Crusade. The king agreed, and a Hungarian army of 2,000 men led by Géza escorted the German emperor's forces. Later on, Frederick camped in Philippopolis, then in Adrianople in the autumn of 1189 to avoid winter climate in Anatolia, in the meantime, he received imprisoned German emissaries who were held in Constantinople, and exchanged hostages with Isaac II, as a guarantee that the crusaders do not sack local settlements until they depart the Byzantine territory. In March 1190, Frederick left Adrianople to Gallipoli at the Dardanelles to embark to Asia Minor. The armies coming from western Europe pushed on through Anatolia, where they were victorious at the Battle of Philomelium and defeated the Turks in the Battle of Iconium, eventually reaching as far as Cilician Armenia.