Marostica area became under the rule of Cangrande I della Scala in 1311. Next year he founded two castles in Marostica, the lower (Castello Inferiore) and upper (Castello Superiore) castle.
The lower castle in the city center is rectangular. After the War of the League of Cambrai, the mayor moved his headquarters from upper to lower castle. The upper castle is a square form building with four little towers on the sides and a large central tower.
There is a 1800m long wall connectiong these two castles.
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.