The Union with Rome, which led to the establishment of the Romanian Greek Catholic Church, in the area inhabited by the Romanian population in northwestern Hungary, known as the Principality of Transylvania, is placed within the conceptual framework of partial unions between Orthodox and Catholic communities after the Union of Brest at the end of the sixteenth century. Following the defeat of the Ottoman Empire at the walls of Vienna in 1683, Austrians focused their political and military interests towards the East, engaging in a large offensive that settled the authority of the House of Habsburg over central and southeastern Europe. Among these regions Transylvania became a part of the Habsburg Empire in 1691.