Isolated and remote, Mértola surprises the visitor with its rich heritage and amazing position. Once known as Myrtillis Romana, the place flourished in the days of the Romans. Its vast walls were not enough to save the town from the Barbarian onslaught that ended Roman rule of the Iberian Peninsula. But, the 8th century arrival of the Moors brought a new period of prosperity. In 1238 the Portuguese king Dom Sancho II took the castle and handed it over to the Order of St. James. By 1300 a new castle had risen from the ruins of the old. The walls remained in constant reconstruction with Spain just across the river.
Today, Mértola is an archaeological jewel, with excavations revealing remains from the town’s many rulers of the past 2000 years. Inside its walls thrives a beautiful town, rich in simple houses, old cannons, and flowers. The vast cistern and castle keep are testaments to the town’s bellicose past. It also boasts the only still-standing Moorish mosque in Portugal. The square mosque, now a church, is a unique example of the lost riches of Moorish Portugal.