But the Ottoman Empire did not annex Hungary after the war and the Hungarian throne was left vacant for several months.[1] Two claimants emerged: Ferdinand I, the archduke of Austria; and János Szapolyai, the voivode (governor) of Transylvania (Turkish: Erdel, western part of modern Romania). Although Szapolyai was backed by a majority of the Hungarian elite, Ferdinand nevertheless declared himself the legal king of Hungary with the support of his older brother Charles V, Holy Roman Emperor. The Ottoman Empire, however, backed Szapolyai and Ottoman Emperor Suleyman I mounted a threat against Austria in two military campaigns (of 1529 and 1532).