Coimbra, side by side with Braga, is the third most important urban center of Portugal after the much larger Lisbon Metropolitan Area and Porto Metropolitan  Area conurbations, and plays a role as the chief city of the central part of the country. The city, which was the capital of Portugal from 1139 to about 1260, has a large archeological site with extensive ruins dating from the time it was a Roman town called Aeminium. Coimbra developed into an important cultural centre, mainly because of the University of Coimbra founded in 1290. The university is one of the oldest in Europe and due to its monumental buildings attracts tourists from around the world.