The united armies of the Holy League expelled the Ottoman troops from Central Europe between 1684 and 1699, and the Principality of Transylvania was integrated into the Habsburg Monarchy. The Habsburgs supported the Catholic clergy and persuaded the Orthodox Romanian prelates to accept the union with the Roman Catholic Church in 1699. The Church Union strengthened the Romanian intellectuals' devotion to their Roman heritage. The Orthodox Church was restored in Transylvania only after Orthodox monks stirred up revolts in 1744 and 1759. The organization of the Transylvanian Military Frontier caused further disturbances, especially among the Székelys in 1764.