Balga was a medieval castle of the Teutonic Knights. The hill of Balga had been the site of an Old Prussian (Warmian) fortress called Honeda, that had been unsuccessfully besieged by the Wettin margrave Henry III of Meissen on his 1237 Prussian Crusade. It was conquered in 1239 by the forces of the Teutonic Order, led by Grand Marshal Dietrich von Bernheim.
The oldest Ordensburg constructed by the Teutonic Order was built from 1239 to control naval traffic on the Vistula Lagoon. With the assistance of Duke Otto I of Brunswick-Lüneburg, the Knights defeated the Old Prussians along the coastline of Warmia and Natangia. The subjugation of these pagans led Duke Świętopełk II of Pomerania to declare war against the Order during the 1242 Prussian uprising, although he was forced to acquiesce. From 1250 Balga was the administrative centre of Kommende Balga and the seat of a Komtur of the Teutonic Knights. Many Komturs at Balga like Winrich von Kniprode or Ulrich von Jungingen later rose to the office of the Grand Master.
In 1499 Grand Master Friedrich von Sachsen had the commandery dissolved. Upon the Prussian Homage, Balga was part of the Polish Duchy of Prussia in 1525 and the castle became the residence of George of Polentz, Bishop of Samland. From 1627, parts of the castle were broken down at the behest of King Gustavus Adolphus of Sweden during the Polish–Swedish War in order to gain building material for the construction of the Baltiysk (Pillau) fortress.
Balga was also the name of the nearby village, after 1945 renamed Vesyoloye, which is now abandoned. Until the end of World War II Balga was in the former German Province of East Prussia; it was the site of one of the final battles of the Wehrmacht with advancing Red Army forces during the East Prussian Offensive, which devastated the castle remains.
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.