Dubingiai Castle was a residential castle in Dubingiai, Molėtai district, Lithuania. The first masonry castle was constructed by Vytautas, Grand Duke of Lithuania, in 1412-1413 on an island, now a peninsula, in Lake Asveja in order to secure the capital Vilnius from attacks from Livonia. No accounts concerning the architecture of Vytautas' castle have survived. It was acquired by Jerzy Radziwiłł prior to 1508. He constructed a new palace in the Renaissance style in the first half of the 16th century. After the death of Jerzy, his son Mikolaj "the Red" inherited the property, causing the town nearby to become an important hub for the Reformation in Lithuania. Barbara Radziwiłł spent five months in the castle after her marriage to Sigismund Augustus in 1547. The palace used to be one of the