The oldest part of the Etelhem Church is a tower, built in the beginning of 1200s. The nave and choir were built around 1300 and sacristy added in 1600s. The interior is decorated with mural paintings made in the 1400s. The well-preserved stained glass in choir window dates from the 1300s. The font was made of sandstone in the late 1100s and wooden crucifix was carved in 1300s. The pulpit dates from 1648 and altar from 1690.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.