Visborg (Wisborg) refers to a fortress in the town of Visby on the Swedish island of Gotland. There was no one fortress called "Visborg", rather it refers to successive fortresses built in Visby (Borg means fortress or castle). Though Visborg is usually a reference to the castle built here by Erik of Pomerania.
Duke Erik Magnusson appears to be the first to construct a fortress in the south-west corner of Visby in the year 1310 as part of a struggle between his brothers for control over the Kingdoms of Norway, Sweden, and Denmark; this brings Gotland under Norwegian control. When Magnus II Eriksson, son of Duke Erik, becomes King of Norway and Sweden it falls under his control. In 1356 Magnus Eriksson gives control of Norway to his son, Haakon VI Magnusson, though he still remains as King of Sweden.
In July of 1361, Danish forces under King Valdemar Atterdag land on Gotland, crush and seize Visby on July 27; killing at least 2000 peasants.
The following year, 1362, Swedish Nobles revolt and declare Haakon Magnusson King of Sweden.
The following year is defining for the future of Scandinavia. In 1363 Haakon and Magnus reconcile and Haakon marries Margaret (Queen Margaret I of Denmark), the daughter of Valdemar, and father & son agree to share the throne of Sweden. The nobles again rose up and offered the crown to Duke Albert of Mecklenburg (King Albert of Sweden).
In 1375 King Valdemar of Denmark dies and Margaret ensures that her and Haakon's infant son, Olaf (Olav), is named heir to the throne. Only five years later, 1380 her husband Haakon, King of Norway, dies making Olaf the heir apparent to both the thrones of Norway and Denmark upon his becoming of age; until that time his mother acts as Queen Regent to both nations. However, in 1387 Olaf dies, and Margaret becomes ruler of Denmark and Norway.
In 1388 King Albert, regarded as a poor King, is driven from Sweden in the hopes that Margaret will assume the throne. After a failed counter-assault by Albert in 1389, Albert and his son are made prisoner. Margaret is named ruler of Sweden, much to the chagrin of the Mecklenburg Dukes. This marks the formation of the Kalmar Union that unifies the three crowns.
In an attempt to destabilize Denmark, the Mecklenburg's hired the Victual Brothers, pirates, to disrupt trade in 1392. They used Visby on Gotland as their fortress from which they were a costly menace to all members of the Hanseatic League. In 1395, after a treaty with the Mecklenburg's, Albert is released with the understanding that he will turn Stockholm over to Margaret in three years.
Margaret and Albert give Gotland to the Teutonic Order, with the pledge that the order will remove the Victual Brothers and their fortress in Visby. Konrad von Jungingen, the Grand Master of the Order, took the Island in 1398 and destroyed Visby.
In 1397 Margaret passes rule of Norway, Sweden, and Denmark to her great-nephew Erik of Pomerania. In 1408 the Teutonic Knights sell Visby to Erik. Three years later he begins construction of the Visborg castle, the most famous Visborg fortress. In 1430the Kalmar Union begins to fall apart. Erik initiates a number of policies that upset nobles in all three of his kingdoms. Hostilities between the King and the nobles escalate until 1439 when Erik is deposed by Karl Knutsson Bonde (later Charles VIII of Sweden) in Sweden and by Christopher of Bavaria, Erik's nephew, in Denmark; Erik was offered the throne of Norway alone, but refused. In response Erik took permanent residence at the castle of Visborg, though never relinquishing his claim to the throne, though by 1440 he had no power outside of Gotland. Christopher of Bavaria reigned as sole monarch until his death in 1448 without an heir. Swedish nobles took the opportunity to make Karl Knuttsson Bonde King of Sweden and Norway; and the Danish named Christian I King of Denmark. This began a long period of warfare between the Kings of Denmark and Sweden over who would once again rule over the three kingdoms of the Kalmar Union. With tensions rising, Gotland became an immediate point of conflict. In 1448 Knuttsson launched an invasion of the island and was able to secure all but the Visby because of the fortifications of Visborg, which was still inhabited by the deposed King Erik. Erik made a deal with Christian I in 1448, because they were family, in which he agreed to cede Gotland to the Danes and renounce his claims to the throne in return for safe passage to Pomerania. Christian agreed and in 1449 a Danish army reinforced the defenses of Visborg by sneaking in under cover of darkness. As the Danes moved in the Swedes evacuated the island. As promised Erik was given safe passage to Pomerania where he ruled the Duchy of Stolp as Erik I until his death in 1459.
Despite numerous challenges, Denmark retains continuous rule of the island until a peace treaty signed in 1645 grants it Sweden for 30 years. Denmark gains it back in 1676, but in 1679 Denmark signs another peace treaty with Sweden in which they agree to return Gotland. As the Danish soldiers were leaving Visby the same year, they blew up the fortress of Visborg. Some fragments of its structure still can be seen in over-looking the harbor in Visby.
After the Fortress
Prince Oscar of Sweden, Duke of Gotland and second in line to the Swedish throne, married without his father's permission, thereby relinquishing his right to succession and royal titles. On February 2, 1892 he was made the first Count Bernadotte af Wisborg by his mother's (Sofia of Nassau) brother Grand Duke Adolphe of Luxembourg as an homage to the old fortress of his dukedom. Including Oscar there have been created four such Counts, three in the 20th century, and all former heirs that lost their throne for marrying without the King of Sweden's consent.
Some versions of F.W. Murnau's 1922 classic horror film Nosferatu take place in Bremen, Germany. In fact the original work of Murnau was supposed to be set in Wisborg (the better restorations of the movie use Wisborg, some of the worst use Bremen and Bram Stoker's names for the characters). The discrepancy results from the work being pieced together from various versions after translation in various countries. The work was filmed in Delft, the Netherlands and Slovakia, so it isn't clear why Bremen was chosen by the later inter-title makers – Bremen doesn't have a beach to explain some of the scenes in Nosferatu. That being said, Murnau's selection of Wisborg is unexplained as well. It is unclear whether he was using Wisborg since no city actually exists with the name or if he understood the relation to Visborg and the town name holds a deeper significance.
- Chronology of Swedish History, 1300–1399, 1400–1499, 1500–1599, 1600–1699 by Ken Polsson
- History of Sweden, 1397–1448 by Alexander Ganse
- Visby Attractions
- History of Sweden, 1448–1523 by Alexander Ganse