The settlement of Heusden, bordering on the river Meuse (Maas), as we know it today dates back to the 13th century, and started with the construction of a fortification to replace the castle that was destroyed by the Duke of Brabant in 1202. This fortification was quickly expanded with water works and a donjon (castle keep). The city of Heusden received city rights in 1318. The castle of Heusden was the property of successive dukes of Brabant, in 1357 it went over to the counts of Holland.
With the construction of ramparts and moats the castle became located within the city's fortifications, and the castle lost its function as a stronghold. The donjon was now used as a munition depot. A disaster marked the end of the castle of Heusden and caused the economic demise of the city; on 24 July 1680 a terrible thunderstorm hit Heusden, and lightning struck the donjon. Sixty thousand pounds of gunpowder and other ammunition exploded, and destroyed the castle. It took the people of Heusden seven weeks to clear the rubble and debris. The castle was never fully rebuilt. However, the original outlines of the main features were restored in 1987.
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.