Alsnö hus

13th-century royal palace ruin on Lake Maelaren island, part of Birka UNESCO World Heritage Site.

Alsnoe hus is the ruin of a 13th-century royal palace on the island of Adelsoen in Lake Maelaren, northwest of Stockholm. Its name lives on in Swedish legal history: the Statute of Alsnoe (1280) was issued here, exempting the nobility from taxes and shaping Sweden's feudal social order. The ruin forms part of Hovgaarden, which together with neighbouring Birka — a major Viking trading centre — has been a UNESCO World Heritage Site since 1993.