The Church of the Holy Trinity, since February 2008 Holy Trinity Cathedral, was built around 1400. The Žilina castle is assumed to be already there as early as the 13th century, of which there are documents from 1318 to 1454. It was originally consecrated to Mary, but in the 16th century it was reconsecrated as the Church of the Holy Trinity. The chapel of John of Nepomuk was added in 1762. The church burned down three times, in 1678, 1848 and partly in 1886. The three naves of the church were originally in Gothic style, but after a reconstruction it was styled to Renaissance style. The last major reconstruction of the church was done in 1942.
The main altarpiece in the main altar depicts the Holy Trinity, the side altars depict Immaculate Conception and the Crucifix, and near the entrance there is a picture of Saint Anne. In the compounds of the church stands separate Burian's Tower, built in the first half of the 16th century. The tower offers a good view of the preserved medieval part of the town.
References:
Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.