It was formed in response to the founding of the Protestant Union, and stayed together thereafter to promote ”the one, allembracing, true church.” It ultimately included 15 bishops, 5 abbots, the city of Aachen, and Bavaria. In addition to confessionalism, the League promoted autonomy of its members and Bavarian influence in the Empire. However, an Imperial attempt to co-opt the League by forcing the admission of Austria resulted in break-up of the original League in 1617. Two years later Bavaria reformed a confessional alliance with neighboring bishoprics, again explicitly excluding Austria. Spain’s intervention in Bohemia in May 1619, lessened concern over Austrian predominance and the Liga was accordingly reconstituted under Bavarian leadership. The ”Army of the Catholic League” gave as much or more aid to Ferdinand II as did Spain during the Bohemian revolt. It scored a signal victory at the White Mountain (November 8, 1620), where it destroyed a patchwork Protestant coalition army led by Anhalt, Mansfeld, and Thurn. That secured Bohemia permanently for the Habsburgs and allowed them to forcibly recatholicize it.

The Liga signed a treaty of neutrality with the Protestant Union at Ulm in 1620 in a joint effort to prevent the war from spreading to Germany; but it could not restrain Ferdinand from pursuing Friedrich V into the Palatinate and thereby widening and prolonging what became the Thirty Years’ War (1618-

1648). From 1621 to 1623 the Liga Army repeatedly outfought its opponents, largely because its commander was Johann Tilly and not the divers incompetents who commanded the Protestant armies. The Liga benefitted in early battles from fighting alongside tough Spanish veterans of the Imperial tercios and against divided enemies and mostly feckless, confessionally indifferent mercenaries. It did not do as well against the fervently Lutheran Swedes when they entered the war in 1630, under Gustavus Adolphus. The reputation of the Liga Army was darkened by participation in the sack of Magdeburg in 1631. The next year, it joined Wallenstein outside Nu¨rnberg, before Alte Feste. On average, the Liga Army fielded 30,000-40,000 troops before 1635, when it was dissolved under terms of the Peace of Prague.