Borckholm Castle was built quite late, because in 1479, by the bishop of Rewel (Tallinn), Simon von der Borch, from which the German name of the castle comes from. The building was erected with permission, and probably also with the help of the Teutonic Order, which was the head of the northern Estonia. This was probably due to the fact, that the land master of Livonia was then a relative of Simon, Bernd von der Borch. Another important reason was the desire to strengthen the north-eastern border of Livonia, threatened by the growing strength of the Grand Duchy of Moscow. The fortifications, however, proved insufficient to stop the attack of the Muscovite troops in 1558, which captured and destroyed the castle. After the withdrawal of the enemy, Borckholm did not return to the power of the bishops. In Swedish times, the stronghold lost the remnants of military significance and passed into private hands.
The castle was erected on the edge of the longitudinal island, on which ran a single, wooden bridge. The central point of the stronghold was a courtyard surrounded by a stone wall, of a regular shape, with a chapel and a well. Most of the castle buildings adjoined the inner side of the defensive wall, equipped with eight towers. Four of them were corner, and four were in the length of the walls. South was the castle gate.
Until today, only a few relics of the walls and a single gate tower have survived from the castle, which after the restoration now houses a small museum.
Borowski T, Miasta, zamki i klasztory, Inflanty, Warszawa 2010.