Between 1499 and 1795 the town was controlled by the House of Nassau (as were Breda in the Netherlands, Dillenburg in Germany and Orange in France) which was also the family of the Princes of Orange who at the end of the Napoleonic Wars became in 1815 the kings and queens of the Netherlands after the termination of the Dutch republic at the hands of revolutionary forces in 1795. The most famous representative of the House of Orange was William I of Orange-Nassau. Also known as William the Silent (1533-1584), who led the revolt of the United Provinces against Spain.
Diest is surrounded by high ramparts, which are partially preserved.
The market place of Diest is surrounded by picturesque houses from the 16th to 18th Century. The town hall is also located here, in the basement of the city museum. Exhibits in the museum include the armour of Philip of Orange and a portrait of René of Orange-Nassau and his wife Anna of Lorraine.
The church of St. Sulpitius is also located on the Grote Markt. It was built in 1417-1534 from brown sandstone, typical of this period. The grave of Philip of Orange can be found here. After the death of his father William I of Orange-Nassau, he became Lord of the city. In the turret on the church a famous carillon made by Pieter Hemony in 1671.
The house "Hof van Nassau" in the centre is worth a visit, along with Gothic church of Our Lady (built 1253-1288) which has an award-winning pulpit. In the Sint Jan Berchmansstraat you can visit the "Gulden Maan" , the house where St. John Berchmans was born.