Transylvania as originally defined in Treaty of Trianon, 27 years earlier, thus confirming the return of Northern Transylvania to Romania. From 1947 to 1989, Transylvania, along with the rest of Romania, was under a communist regime. The ethnic clashes of Târgu Mureș occurred between ethnic Romanians and Hungarians in March 1990 after the fall of the communist regime and became most notable inter-ethnic incident in the post-communist era. The Transylvanian Plateau, high, is drained by the Mureș, Someș, Criș, and Olt rivers, as well as other tributaries of the Danube. This core of historical Transylvania roughly corresponds with nine counties of
Early German colonists in Transylvania devastated and remained depopulated after the Mongol invasion of 1241. During the following years he laid the foundations to "Villa Nympz" (Nimesch), a fortified peasant village in a side valley of the Great Kokel River near Medgyes.<ref> Despite of all future historical tribulations and misfortunes, Medardus and his descendants, later known as the Maiterth family, managed to cultivate the former wilderness and transform it into rich and fertile farmland (agriculture, viticulture, stockbreeding). Early German colonists in Transylvania Medardus de Nympz is the Latinized name of Medard zu Nimesch, an early medieval German colonist in Transylvania. Born around 1215 in the