The first stone church in Vihti was built in the end of Middle Ages, probably between years 1500-1520. Unfortunately it was located to a very soft ground and structures started to fall apart in the 17th century. Until 1801 humidity was damaged church so much that local municipality of Vihti decided to sell the church. Woods and stones were ripped off and used as part of local barns.
The church was finally destroyed in storm 1869 when western wall collapsed. Nowadays there are only ruins left of the church and the stone sacristy which is used in ceremonies.
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.