On March 30, 1599 Sigismund Báthory abdicated the throne in favor of his cousin, Andrew Báthory (1599). The new prince was loyal to the Poles and promptly demanded that Michael the Brave accept his suzerainty. The latter secured the emperor's approval for an invasion of Transylvania and attacked the principality where the Székelys also joined him. He defeated his opponent at Şelimbar on October 28, 1599 and entered Alba Iulia. Here the Diet recognized him as imperial governor. He respected the traditional organization of Transylvania, and even crushed a revolt of the Romanian peasants, but forced the Diet to relieve the Orthodox priests of feudal obligations. In the spring of 1600, he invaded Moldavia in the name of the emperor and established control over it. In July he even proclaimed himself "prince of Wallachia, Transylvania, and all of Moldavia" in Iaşi, thus bringing about the union of the three principalities.