Trelleborg is a city in Skåne in southernmost Sweden. Trelleborg has been populated for at least one thousand years. In the 10th century or earlier, a Trelleborg (ring fortress) was built by Danish Vikings. It was rediscovered in the 1990's, and rebuilt, and now it hosts activities every summer. The first written mention of Trelleborg, in the scarce Swedish medieval sources, is from 1257, when Trelleborg and the adjacent city Malmö where presented as a wedding gift from the Danish royal family to the Swedish Prince Valdemar. It was soon reconquered by the Danes and it belonged to Denmark until 1658, when the entire district Terra Scania was lost to Sweden in a war. In the medieval times, Trelleborg became an important merchant city as merchants from Germany came to trade herring. In April 1619, the Danish King decided that one merchant city on the coastal line was sufficient and revoked Trelleborg's status as a merchant city to favour Malmö.