He was the son of István Wesselényi, royal court counselor of King Ferdinand II of Austria. He was raised at the Jesuit school in Nagyszombat (Trnava) where he catholicized. His enormous physical strength and intense temperament predestined him for a military career. In his young ages, he participated in several battles against the Ottoman Turks. He also helped King Władysław IV of Poland with a Hungarian team against the Russians and Tatars and this deed was rewarded with Polish citizenship and a valuable estate. He was raised to the rank of count by Ferdinand II of Austria and was also appointed commander of the castle of Fülek (Filakovo). In 1647, he was appointed general and as such he fought against the Swedes and later against prince György Rákóczi of Transylvania. In 1644, he seized