The earth and timber stronghold Gerdauen was constructed by the Teutonic Knights in 1270. After a subsequent Prussian uprising, the Knights were too weak to keep hold of all their fortresses. Gerdauen was burnt down, but once the Prussian uprising was put down, the Teutonic Knights returned here and began to raise new fortifications. By 1310, a new stronghold had been completed. At that time it was guarded by embankments, moats and shelters. Inside the ring of fortifications, stone and brick buildings for a convent of Teutonic brothers were constructed.
Initially the Knights planned that Gerdauen would become a seat of a commander, known as komtur. But this idea was soon relinquished because of the proximity to the Lithuanian lands and frequent attacks staged by Lithuanian troops. Gerdauen for example was attacked in 1336, 1337 and in 1366.
Although in 1406 Gerdauen Castle was surrounded by a ring of fortified walls less than half a century later, in 1455, which was during the Thirteen Years' War, the fortress was severely damaged. In 1670 it stood empty. Soon afterwards it was sold to a private owner. All that had remained of the original buildings were the cellars.
In 1872 a new beautiful palace was raised on this location. Gerdauen flourished until 1814, that is until the outbreak of World War One. In that year, the town was a witness and a victim of a bloody fight with the Russian army. Gerdauen was not rebuilt until 1921.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.