Matthew III Csák
At that time the Kingdom of Hungary was split into several de facto principalities, and young Wenceslaus was only accepted as the King of Hungary by the rulers in Upper Hungary (Matthew III Csák), in modern day Burgenland (the Güssings [Kőszegis]) and on territory around the capital, Buda. But the Abas and Matthew Csák switched sides in 1303 and started to support Wenceslaus' rival Charles Robert of Anjou. Consequently, the young Wenceslaus, in Ofen (Buda), became afraid and wrote to his father in Prague for help. His father took a large army and invaded Buda, but having considered the situation, he took his son and the Hungarian crown and returned to Bohemia (1304). Ivan Kőszegi was named to represent Wenceslaus III in Hungary.