Visby (vēsˈbə) [key] or Wisby wĭzˈbē, city (1990 pop. 20,990), capital of Gotland co., SE Sweden, on Gotland Island and on the Baltic Sea. It is an industrial center and a popular resort and has a modern ice-free port. Manufactures include cement and refined sugar. The city is a Lutheran episcopal see. Visby was a pagan religious center. In the 11th cent. it became a prominent international trade center of the Hanseatic League. An independent republic, the city was the commercial center of N Europe, minting its own coins and developing an influential international maritime code. The ruins of 10 fine churches and the restored Cathedral of St. Mary, all from the 12th and 13th cent., testify to its former greatness. Visby's decline began in 1280, when Sweden conquered Gotland while the city was suffering civil strife. It was sacked (1361) and captured (1362) by the Danes, who returned (1370) it to the Hanseatic League. Pirates made it their stronghold for the next two centuries, and its trade was taken over by Lübeck. Visby passed to Denmark in 1570, and again came under Sweden in 1645. The city only began to recover its trade in the 19th cent.