Opochka
Opochka fortress was founded in 1414. Already in 1426 it defeated an attack by the troops of the Grand Duke of Lithuania Vitovt. In the 15th-16th centuries Opochka defeated many attacks by the troops of the Grand Duchy of Lithuania. The fortress was saved by its insular position, which made sieges and assaults very difficult. In 1517, the Polish king Sigismund I called Opochka a "demonic village", after the failure of his campaign. Opochka, apparently in 1581, turned out to be the only Pskov fortress, that was not taken by the troops of Stephen Batory: the garrison simply sat out on the island for the entire campaign.
Tags: castles and fortresses, 15 century, 16 century, Routes of the Livonian War, Pskovian Land