The origins of Avila, also called Avila de los Caballeros, date from pre-Roman times, and became part of the Roman province of Lusitania. In 714 the city was taken by the Moors, and retaken by King Alfonso VI in 1085. The walls of Avila, with its towers, surrounding the old city, date from the 11th and 12th centuries, has a total length of 2.5 km (1.5 miles) and is on average 12 meters (40 feet) high. The city is also the birthplace of St Teresa (1515 - 1582).