Westphalia to be Catholic. Osnabrück was divided almost equally between Catholicism and Protestantism. Parts of Westphalia came under Brandenburg-Prussian control during the 17th and 18th centuries, but most of it remained divided by duchies and other areas of feudal power. The Peace of Westphalia of 1648, signed in Münster and Osnabrück, ended the Thirty Years' War. The concept of nation-state sovereignty resulting from the treaty became known as "Westphalian sovereignty". After the defeat of the Prussian Army by the French at the Battle of Jena–Auerstedt, the Treaty of Tilsit in 1807 made the easternmost portion of today's Westphalia part of the
Treaty on the Functioning of the European Union Maastricht treaty, which led to the formation of the European Union, saw the EEC Treaty renamed as the Treaty establishing the European Community (TEC) and renumbered. The Maastricht reforms also saw the creation of the European Union's three pillar structure, of which the European Community was the major constituent part. Following the 2005 referenda, which saw the failed attempt at launching a European Constitution, on 13 December 2007 the Lisbon treaty was signed. This saw the 'TEC' renamed as the Treaty on the Functioning of the European Union (TFEU) and, once again, renumbered. The Lisbon reforms resulted in the merging