Uri, along with Central Switzerland as a whole, resisted the Swiss Reformation and remained staunchly Roman Catholic. As the Reformation spread through the Swiss Confederation, the five central, catholic cantons felt increasingly isolated and they began to search for allies. After two months of negotiations, the Five Cantons formed (the Christian Alliance) with Ferdinand of Austria on 22 April 1529. After the Battle at Kappel of 1531, in which was killed, the Confederacy was on the point of fracturing along confessional lines. The peace treaty after the Kappel war established that each canton would choose which religion to follow, but peace between Catholic and Protestant cantons remained brittle throughout the early modern period.