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 at the end of an elongated island to which a single wooden bridge led. The central point of the stronghold was a courtyard surrounded by a stone wall, similar to a regular quadrilateral, on which there was a chapel and a well. The defensive wall was not very massive, it was about 1.5 meters thick, but had a significant height of up to about 15 meters. Most of the long and narrow castle buildings adjoined its inner side, and from the outer face it was equipped with eight towers. Four of them were corner, and four were along the length of the walls. The southern one served as a castle gate with a passage pierced in the ground floor. The remaining towers had cylindrical, semicircular and quadrilateral forms, all of them almost entirely extended in front of the perimeter of the defensive walls.
The southern gate tower, erected on a quadrilateral plan with dimensions of 7.5 x 7.5 meters, passing into an octagonal in the upper part, was 21 meters high, three storeys in the quadrilateral part and two more in the polygonal part, connected with each other by short stairs in thickness wall. In addition, on the second floor, it was connected to the defensive wall-walk in the crown of the defensive circuit. Only the gate passage in the ground floor was covered with the vault, while the remaining floors were separated with flat timber ceilings. Some of them also had to fulfill residential functions, as they were equipped with fireplaces, wall niches and a drain for water or waste. Probably due to the island location of the castle, the gate was not equipped with a drawbridge.
It is assumed that the representative rooms were located in the castle on the eastern side of the gate tower, because there a hewn stone with the coat of arms of the von der Borch family was found. The outer bailey adjacent to the main castle on the south side was not fortified with stone walls, and the wooden domestic buildings were protected only by a palisade.
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.
Alttoa K., Bergholde-Wolf A., Dirveiks I., Grosmane E., Herrmann C., Kadakas V., Ose J., Randla A., Mittelalterlichen Baukunst in Livland (Estland und Lettland). Die Architektur einer historischen Grenzregion im Nordosten Europas, Berlin 2017.
Borowski T., Miasta, zamki i klasztory. Inflanty, Warszawa 2010.
Tuulse A., Die Burgen in Estland und Lettland, Dorpat 1942.