Mariefred Charterhouse, sometimes referred to as Gripsholm Charterhouse, was a Carthusian monastery, or charterhouse. It was the only Carthusian monastery in Scandinavia, and one of the last monasteries established in Sweden before the Reformation.
The establishment of a Carthusian monastery in Sweden was brought about by the efforts of Jakob Ulvsson, Archbishop of Uppsala, and Kort Rogge, Bishop of Strängnäs, who in 1493 persuaded Sten Sture the elder, Regent of Sweden, to have the monks Fikke Dyssin and Johannes Sanderi together with two lay brothers sent from the Marienehe Charterhouse near Rostock to Sweden for a meeting with the riksrådet (Privy Council of Sweden). Later that year Sten Sture enfeoffed the Carthusians with the Gripsholm estate in Selebo härad in Södermanland and in 1502 gave them other lands round about.
The monastery was built on the high ground where Mariefred church now stands, built on the charterhouse ruins in the 1620s, close to Gripsholm Castle. The monastery church was dedicated on 15 February 1504.
Mariefred Charterhouse was short-lived: in 1526 it was one of the first monasteries secularised by Gustav Vasa. In December 1525 he claimed its assets from the heirs of Sten Sture the Elder, who had given the estate to the monastery on the condition that it should pass to the right heirs of the monastery if it were ever wound up. This claim was legitimated by the Privy Council in January 1526.
Virtually no trace of the monastic buildings now remains above ground: Gustav Vasa had them dismantled for the construction of Gripsholm Castle. A cellar and a few traces of walls have been discovered to the south of the church. A small collection of stones discovered during excavations in the monastery grounds, is in the current Mariefred church tower.
References:First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.