Answer
Sigismund Báthory replaced General Giorgio Basta in Transylvania due to significant opposition from the Transylvanian nobility. The nobility had been opposed to Basta since his arrival in 1603, and they were particularly incensed by his treatment of the Hungarian nobles. In 1606, the Transylvanian nobility revolted against Basta and forced him to flee the country. Báthory was then installed as the new prince of Transylvania.