Following the 1526 Battle of Mohács, during which the Ottomans conquered much of Hungary, leaving Transylvania under the rule of local Princes ("see Ottoman Hungary"), Roman Catholicism entered a period of regression, and was later confronted with the success of Reformation. The first community to embrace a Protestant creed were the Transylvanian Saxons, most of whom adhered to the Lutheran Augsburg Confession as early as 1547, followed soon after by large groups of the Hungarian population, who converted to Calvinism. The provostship of Szeben ceased to exist entirely. Catholicism attempted to reestablish itself as George Martinuzzi, a Catholic cleric, took over rule of Transylvania, but again declined after Martinuzzi was assassinated in 1551.