The Huis ter Kleef castle was probably built in the late 13th century. In 1403 it was given to Margaret of Cleves (c.1375-1411), and has since retained that name. During the Siege of Haarlem in 1572 it was the headquarters of the Spanish army, under the leadership of the duke of Alva. It was blown up in 1573 and badly damaged, the rubble was used for city expansion. The house nearby with a tower called the 'Kaatsbaan' was long considered the only building left standing, though recent archeological research suggests that the foundations have older stones than the rest and perhaps it was itself rebuilt after the explosion.
The property changed hands several times until it was purchased by the city of Haarlem in 1713. Stones from the central castle ruin can still be seen in surrounding buildings. The Kaatsbaan was used as a residence for former owners and is now also in use by the city gardens.
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.