Ferdinand was unable to protect eastern Hungary against the Ottomans. At Suleiman's urging, the Transylvanian Diet in 1556 persuaded John Sigismund and his mother to return to Transylvania, where she ruled her son's realm until her death in 1559. A wealthy lord, Melchior Balassa, rebelled against John Sigismund in late 1561, and Ferdinand gained control of most counties outside Transylvania. The Székely people, whose liberties had been restricted in the 1550s, also rose up against John Sigismund, but he crushed the rebellion. During the ensuing war against the Habsburgs, the Ottomans supported John Sigismund, and he paid homage to Suleiman in Zemun in 1566. The 1568 Treaty of Adrianople concluded the war, confirming John Sigismund in the eastern territories of the medieval Kingdom of Hungary (Transylvania and "Partium").