Kreva Castle is the ruins of a major fortified residence of the
Grand Dukes of Lithuania (
Gediminas and
Algirdas) in the village of
Kreva,
Belarus. Algirdas's brother
Kestutis was imprisoned and murdered in the Kreva Castle in 1382. Kreva Castle is situated at an elevation of 220 m. The
Union of Krewo (Act of Krewo), the first
step towards the
Polish–Lithuanian Commonwealth, was signed in the castle three years later. The castle was sacked by the
Crimean Tatars in the early 16th century and stood unoccupied for a long time. By the 19th century, much of the walls had crumbled away. The
World War I dealt a final blow to the decaying structure, since the castle stood on the front line between Russian and German armed forces. In 19th and 20th centuries, the ruins were partially conserved, particularly by Poland in 1929. However, the monument crumbles further.