In response, in February 1621, Jenatsch led a force of anti-Habsburg troops to attack Rietberg Castle, the home of a leader of the pro-Catholic faction, Pompeius Planta. They surprised Planta and according to legend he was killed by Jörg Jenatsch with an axe. The murder of Planta encouraged the Protestant faction and they assembled a poorly led and disorganized army to retake the Valtellina and other subject lands. However, the army fell apart before they could attack a single Catholic town. This Protestant invasion provided the Spanish and Austrians an excuse to invade the Leagues. By the end of October, Spain and Austria had occupied all of the Grisons. The resulting peace treaty of January 1622, forced Grisons to cede the Müstair, the Lower Engadine and Prättigau valleys. The treaty also forbade the Protestant religion in these valleys. In response, in 1622, the Prättigau valley rebelled against the Austrians and drove them out of the valley. The Austrians invaded the valley twice more, attempting to reimpose the Catholic faith, in 1623–24 and 1629–31.