The Livonian Order built a fortified castle on the largest island in Lake Alūksne – Marijas Island (Pilssala Island) in 1342.  It was linked to the land by a 120 m drawbridge.  The castle had several forecastles, and it was regularly modernised and expanded until the end of the 17th century.  It was one of the largest Livonian Order Castles, with similar ones found in Vastelina and Izborsk.  Defensive barriers were put up around the castle, which survived until the Great Northern War.  Its central part was blown up by the defeated Swedish military in 1702, after which Russians completely sacked it.  All that is left are the castle ruins on the island, which is now linked to Alūksne and Temple Hill by two wooden bridges.  An open-air stage alongside the castle ruins is used for various public events.