The Old Swiss Confederacy a "de facto" independent state throughout the early modern period, although still nominally part of the Holy Roman Empire until 1648 when the Treaty of Westphalia ended the Thirty Years' War. The Swiss Reformation divided the confederates into Reformed and Catholic parties, resulting in internal conflict from the 16th to the 18th centuries; as a result, the federal diet () was often paralysed by hostility between the factions. The Swiss Confederacy fell to invasion by the French Revolutionary Army in 1798, after which it became the short-lived Helvetic Republic. The adjective "old" was introduced after the Napoleonic era with ,
League of the Rhine of the 1648 treaty of Westphalia, the treaty which had made the League possible by authorising the German princes, immediate vassals of the Emperor, to conclude alliances between themselves or with foreign states. On August 14, 1658, the League of the Rhine was formed by: The League fielded a force of 6000 to fight on the side of France and the Empire against the Ottomans, seeing action in the 1664 Battle of Saint Gotthard. The League was promulgated to last for three years, and this was later twice extended. It officially ended in August 1667, its end should in fact