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 "Teatro romano de Mérida" was constructed in the years 16 to 15 BCE. It has undergone several renovations, notably at the end of the 1st century or early 2nd century CE when the current facade was erected, and another at the time of Constantine I, which introduced new decorative-architectural elements and a walkway around the monument. Following the theatre's abandonment in Late Antiquity, it was slowly covered with earth. In its time it had a seating capacity of 6,000. The diameter is about 86 meters.