Stenberga Slott

Finland, Finland

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Stenberga Slott, also known as Stenberga Castle or Teinperi, is the ruin of a small medieval fortress located in Masku, near Naantali in southwestern Finland.

Built mainly of stone on a steep rocky hill that was once close to the sea, it likely served as a defensive stronghold controlling access to the surrounding waterways and settlements. Historians generally date the castle to the late 14th or early 15th century, although some theories suggest it may be older.

The site later became associated with a Bridgettine monastery in nearby Naantali, and the castle was eventually abandoned and fell into ruin. Today, only limited remains of the castle survive, but the site is valued as an important part of Finland’s medieval heritage. Its secluded setting and historical significance offer a glimpse into the region’s early defensive and religious history.