The bridge to the main castle gatehouse

Trakai Island Castle is located in Trakai, Lithuania on an island of Lake Galvė. The castle is sometimes referred to as "Little Marienburg". The construction of the stone castle was begun in the 14th century by Kęstutis, and around 1409 major works were completed by his son Vytautas the Great, who died in this castle in 1430. Trakai was one of the main centers of the Grand Duchy of Lithuania and the castle held great strategic importance.

Trakai Island Castle was built in several phases. During the first phase, in the second half of the 14th century, the castle was constructed on the largest of three lake islands by the order of Grand Duke Kęstutis. The construction of Trakai Island Castle was related to the expansion and strengthening of the Trakai Peninsula Castle. Kęstutis moved his main residence and his treasury to the Island Castle.

The castle suffered major damage during an attack by the Teutonic Knights in 1377. After the assassination of Kęstutis, a power struggle between Jogaila and Vytautas the Great for the title of Grand Duke of Lithuania began. The castle was besieged by both sides. Soon after the reconciliation between Jogaila and Vytautas, the second phase of construction started and continued until 1409. This phase is regarded as the major development in the history of the castle. Apparently, during the truce with the Teutonic Order, the construction works were supervised by the Order's stonemason Radike, four years before the Battle of Grunwald.

During the second phase, two wings were added, and on the southern side a 6 story (35 m. high) donjon was built. The donjon had movable gates which separated the palace from the forecastle. The donjon was used for several functions; besides serving as another defensive structure, it had a chapel and living quarters. It was linked to the multistory Ducal Palace, which had an inner yard. The inner yard had wooden galleries, which ran around the inner wall; these galleries were used to access various support facilities without going inside the palace itself.
The entire southern wing of the southern palace was used for the Ducal Hall. This hall was around 10 x 21 meters in size, and only the Upper Palace in the Vilnius Castle Complex managed to surpass it. The Ducal Hall has preserved some of its original décor.

The principal construction material was so-called red Gothic bricks. Stone blocks were used only in the foundations and the upper parts of buildings, towers and walls. The castle was decorated in a variety of ways, including glazed roof tiling, burned bricks, and stained glass windows. Its overall style after the second construction phase could be described as Gothic with some Romanesque features.