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 ,
Battle of the Dunes (1658) The victory at the Battle of the Dunes and its consequences would lead to the end of ten years of war with the signing of Treaty of the Pyrenees. By this treaty France gained Roussillon and Perpignan, Montmédy and other parts of Luxembourg, Artois and towns in Flanders, including Arras, Béthune, Gravelines and Thionville, and a new border with Spain was fixed at the Pyrenees. The 1659 treaty also required the Spanish king to recognise and confirm all French gains in the 1648 Peace of Westphalia. The defeat of the Spanish relief force and the taking of Dunkirk ended the