Settlements dating from the Stone Age have been found in Óbuda. The Romans built there Aquincum, the capital of Pannonia province. Hungarians arrived after 900 and it served as an important settlement of major tribal leaders, later kings. The site was the location of royal and ecclesiastic foundations. King Béla IV built a new capital after the 1241-42 catastrophic Mongol invasion in Buda, somewhat south of Óbuda. In the fourteenth century, Óbuda featured a convent of the Poor Clares.