The castle was erected in 1345 by the land master of Livonia, Buskhardt von Dreileben, as a new administrative center for estates of Order on Saaremaa and the surrounding islands, located directly by the sea. It was necessary because the previous stronghold performing this function, the castle in Peude, was destroyed during the Estonian uprising and never rebuilt.
The first fortifications were probably wooden, only a few years later the national master Goswin von Herreke replaced them with stone. Soneburg was away from the regions of the main conflicts, so it was continuously in the hands of the Teutonic Knights up to the secularization of the Order, and even a little longer, because the German, secularised crew ruled the castle until 1564. It was then that it came under Danish rule and became a border stronghold between Denmark and Sweden. Four years later it was taken over by the Swedish army, for whom it was an important bridgehead for further expansion. For this reason, the castle was reinforced by the north-eastern artillery bastion. However it turned out to be insufficient, and after a few years the Danes recaptured the castle. Fearing that it will be occupied again, the Danish king Frederick II ordered the castle to be blown up. Since then, Soneburg has been in ruin.
The castle consisted of a single, three-storey house. The representative rooms were on the first floor, they were warmed, as evidenced by the preserved hypocaustum furnace. The ground floor and the attic had economic and defense functions. The communication between the floors was ensured by stairs placed in the thickness of the external wall. The house was surrounded by an irregular defensive wall equipped with at least two towers adapted to use firearms. Inside, additional buildings of an economic nature were built. A small settlement developed near the castle, next to which there was a seaport.
Today, most of the outer walls of the castle and towers do not exist. The main house lost part of the first and the entire second floor, and the rubble formed a barrier around the lower parts of the building. Thanks to this, the whole ground floor with vaults and part of the first floor has survived to this day. These rooms have preserved their medieval character and have been made available for exploration after cleaning and securing. It is a pity that the monument from the outside has not been secured in a more eye-friendly way, but only by a tin-metal structure.
Borowski T, Miasta, zamki i klasztory, Inflanty, Warszawa 2010.