The Mongol invasion of Hungary brought severe destruction in 1241–42, causing the disappearance of dozens of villages. After the withdrawal of the Mongols, new fortresses, made of stone, were built. Cumans settled in the lowlands around 1246. Their traditional nomadic way of life gave rise to conflicts with their neighbors for decades. Charles I of Hungary held his royal residence in Timișoara between 1315 and 1323. Colonization contributed to the development of the noblemen's estates in the . The presence of Vlachs (or Romanians) in the Banat Mountains can be documented from the same century. The expansion of the Ottoman Empire in the Balkan Peninsula forced thousands of Bulgarians and Serbs to leave their homelands and settle in Banat. Louis I of Hungary made several attempts to convert his Orthodox subjects into Roman Catholicism in Banat in the 1360s. The region became an important frontier zone after the Battle of Nicopolis in 1396. The "ispáns" (or heads) of Temes County were tasked with the defence of the frontier, which enabled them to unite most counties of Banat under their rule and to administer all royal fortresses in the region.