Philip, the Archbishop of Salzburg, who was Ottokar’s cousin, had trouble with his chapter, upon which he was deposed, War with Bavaria and another archbishop appointed in his place. As the deposed archbishop refused to give up his office, war broke out, and Ottokar went to the assistance of his cousin. He was defeated, and compelled to leave the country in disgrace, after giving up several towns and fortresses to the Bavarians.
Ottokar, however, soon retrieved his military honor by a series of brilliant victories over the Hungarians. War with Hungary Bela, the King of Hungary, declared war against Ulric and Philip, the Dukes of Carinthia, who appealed for aid to Ottokar. At the same time the people of Styria rose in rebellion against the Hungarians, and turned for help to Ottokar, promising to make him their ruler if once free from the Magyar yoke. Ottokar granted the request, sent an army into Styria, which drove out the Hungarians, and established a Bohemian nobleman in the government. This proved the beginning of a great war between Hungary and Bohemia. The rulers of both countries made vast preparations for the coming contest. King Bela impressed into his service all the able-bodied men of his dominions, besides making alliances of friendship with the neighboring States. He soon had an army of 140,000, composed of Magyars, Croats, Bosnians, Serbs, Bulgarians, Italians, Greeks, and even a regiment of Tartar mercenaries.
Ottokar collected his troops from Bohemia, Moravia, and Austria, several German princes also sending some troops. His army numbered 100,000 men, among them a regiment of 7,000 cavalry, composed entirely
