Stolpe Abbey was the first monastery in Pomerania. Ratibor I, Duke of Pomerania, founded the abbey on 3 May 1153 in memory of his brother Wartislaw I. Wartislaw, who had subdued the area and converted its people to Christianity in the late 1120s, was killed near the site of the future monastery; according to legend he was murdered by a Liutician pagan.
The abbey was settled by Benedictine monks from Berge Abbey near Magdeburg. The Pomeranian dukes and the Counts of Gützkow granted the new foundation extensive lands in the vicinity. In 1164, a meeting between the Duke of Saxony, Henry the Lion, and King Valdemar I of Denmark was held here.
In 1304, the abbey became part of the Cistercian Order, and was made a daughter house of Pforta Abbey. In 1305, Kärkna Abbey (also known as Falkenau Abbey) and in 1319 Padise Abbey, both in Estonia, were put under the authority of Stolpe.
In 1534, Stolpe Abbey was dissolved in the course of the Protestant Reformation. The Thirty Years' War made a battleground of Stolpe and left the abbey buildings in ruins.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.