In 1572–89, Johan III had the castle completely rebuilt. The medieval castle was transformed into a magnificent renaissance palace. The construction of the castle into a unified baroque palace began in 1652 and lasted until 1709. However, the rebuilding of the castle was never completely finished. Instead, the castle was left to more or less decay until 1803.
In the middle of the 19th century, there were calls to preserve and maintain the dilapidated castle. In 1860 the first state funds for maintenance were granted and used to rebuild windows and gun ports. In the 1880s, arches and stairs were also repaired in the castle. During the last 100 years, major renovation efforts have been made to preserve Borgholm Castle and today the castle is a well-visited place for tourists.
The history of Borgholm Castle stretches back 800 years. What remains nowadays, is the ruin of the magnificent Baroque palace built by Karl X Gustav in the middle of the 17th century. Over the centuries, the castle has been crowded with people, from kings and their families, architects and castle wardens to farmers, prisoners, prison guards, industrialists and crofters. Initially, the foundations of the castle were constructed as a keep surrounded by a bailey as early as the 12th century. Since then they have been developed in step with the history of Borgholm Castle.
The 12th century was a turbulent time for Northern Europe. In order to protect the sparsely populated areas from piracy and looting, a chain of defensive fortifications was built. During the same period, the oldest known part of Borgholm Castle was also constructed, a strong keep, which was then further strengthened during the 13th century. During the 1360s, the older medieval castle was rebuilt into a square stronghold. The royal castle in Borgholm became one of the country’s most important fortresses.