A confederated realm of German princedoms had been in existence for over a thousand years, dating to the Treaty of Verdun in 843. However, there was no German national identity in development as late as 1800, mainly due to the autonomous nature of the princely states; most inhabitants of the Holy Roman Empire, outside of those ruled by the emperor directly, identified themselves mainly with their prince, and not with the Empire as a whole. This became known as the "practice of "kleinstaaterei"", or "practice of small-statery". By the 19th century, transportation and communications improvements brought these regions closer together. The Empire was dissolved in 1806 with the abdication of Emperor Francis II during the Napoleonic Wars. Despite the legal, administrative, and political disruption caused by the dissolution, the German-speaking people of the old Empire had a common linguistic, cultural and legal tradition. European liberalism offered an intellectual basis for unification by challenging dynastic and absolutist models of social and political organization; its German manifestation emphasized the importance of tradition, education, and linguistic unity. Economically, the creation of the Prussian "Zollverein" (customs union) in 1818, and its subsequent expansion to include other states of the German Confederation, reduced competition between and within states. Emerging modes of transportation facilitated business and recreational travel, leading to contact and sometimes conflict between and among German-speakers from throughout Central Europe.