Treaty of Nikolsburg

The Treaty of Nikolsburg, signed on December 31, 1621, concluded a conflict between Gábor Bethlen, Prince of Transylvania and briefly titular King of Hungary, and Ferdinand II, Holy Roman Emperor. Bethlen, a Protestant, had seized much of northern Hungary and the crown of St. Stephen during the Thirty Years' War while Ferdinand was occupied with other revolts.12

Under the treaty, Bethlen renounced the Hungarian throne and returned the crown of St. Stephen. In return, Ferdinand II reaffirmed the 1606 Treaty of Vienna, guaranteeing religious freedom for Protestants in Hungary and promising to convene a national Diet. Bethlen retained his title as Prince of Transylvania and Hungary, gained additional territory in northeastern Hungary, and secured a duchy in Silesia. This treaty was a significant event in the ongoing struggle for control and religious freedom within Hungary during this period.12