In the Roman Empire, the city was known as "Emerita Augusta", the capital of the province of Lusitania. It was founded in 25 BC by Emperor Augustus as a colony for the veteran soldiers ("emeritus") of the Roman legions. The city was very important in Roman Hispania. It was endowed with all the comforts of a large Roman city and served as the capital of the Roman province of Lusitania. For centuries, until the fall of the Roman Empire, Mérida was an important economic, military, and cultural center. Following invasions from the Visigoths, Mérida remained an important city of the Visigothic Kingdom of Hispania in the 6th century. In 713, the Arabs conquered the city and devastated it. Even under Islamic rule, Mérida remained a bishop's seat until it was moved to Santiago de Compostela in 1119. In 1230 the Christian troops under Alfonso IX conquered Mérida during the Reconquista. The "Anfiteatro de Mérida" is a ruined Roman amphitheater. Emerita Augusta, was founded in 25 BC the amphitheatre itself was completed in 8 BC. The building was intended for gladiatorial fights and combats between beasts or men and beasts. The stands had a capacity of approximately 15,000 spectators. The amphitheater is part of the Archaeological Ensemble of Mérida, which is one of the most extensive archaeological sites in Spain. It was declared a World Heritage Site by UNESCO in 1993.