Visby was probably established the year 897. At that time, big parts of Gotland were swamp areas. The downtown ascends from the coast-line terraced up against Klinten 40 meters above sea level.
  Visby's settlement is considered constructed after a regulated planning system with narrow streets. In the center of the current downtown, fresch water was in good supply. The water became, like the harbour, an important reason for the development of Visby to a medieval large town. You can still listen to the spring´s sound today from the cellar of St. Karin's ruined monastery.
  During the viking period Visby began to assume the caracter of a built-up area. As from the end of the 11th century Gotland dominated the lucrative long-distance trade with Russian goods, directed towards Western Europe.
  The population of Visby increased with the Germans' immigration in the middle of the 12th century, as rumours about Gotlanders' accumulated wealth and success became widespread. Visby became a big transit center for merchants all around the Baltic Sea.
  It's hard to tell how many people lived in this ultra modern town with lofty stone houses and more churches than anywhere else in Sweden. About 3000 people live 'behind the walls' today, estimations for the medieval period are about 6000.
  Visby got its first latrine system when the houses were built with combined privy and rubbish chute. Several latrine chambers were connected together in a system that ended in the harbour.

  Churches: At The Cliff Terrace was since 1190 a German guest church, like probably one Russian in the quarter of "The monk". In the NE corner of this area bishop Albert from Riga built a guest church, dedicated to St Jakob, and during 1220 the Dominicans started to build their friary and the big church of St Nikolai. In 1240 the German Order in Visby probably started to raise the hospitality and the church of 'Helge And', while the Franciscan Order were residing above "Stora Torget" [The big square] in 1233. St Per and St Clemens, probably also St Olof, became churches before 1200.
  The harbour entrance was defended by Kruttornet [Gun powder tower]. It connects with the so-called sea wall which was built in the middle of the 13th century. All these buildings show the fast growth of Visby at that time.

  Visby enjoyed full membership in the Medieval trading organisation, the Hanseatic League (Hansa), but it wasn't the membership that gave rise to the grandeur of Visby. Merchants on Gotland had been traders before that, with contacts around the Baltic Sea, also engaged in long-distance trading through Russian interior and as far away as to the Christian Bysans. And it was in trading solidarity with the farmer-merchants. When the merchants in Visby broke away from the Gotlandic union and joined the town-based union of Hansa, it probably led to the civil war of 1288. During the 14th century Visby lost its position as trading center for goods to Russia and the Baltic countries. In 1350 the Great Plague came to Gotland, and only 11 years later in 1361 the Danish king Valdemar Atterdag invided Gotland and Visby. It was in 1645 that Gotland once again became a part of Sweden.