Between the market square and the Woluwelaan stand the remains of the castle of the lords of Diegem: the gatehouse with its two late 15th-century towers, and the moat. The castle used to be called the Seyp, a word meaning ditch or brook. It owes its present name to its last private owner, August Ulric Marga.
A moated castle
In 1738 lord Jan Antoon Happart described it as a country house with a drawbridge and water all around, with an avenue, tenant farm, barn and stables. An engraving of 1730, drawn by J. Van Croes and engraved by Henricus Causé, shows a handsome Gothic manor with tall windows, surrounded by moats, with a stone bridge and a slender residential tower in front. The right wing later disappeared; around 1900 there was still a building with one upper floor and a mansard roof behind the gatehouse.
The gatehouse has kept its defensive character. Two towers with conical roofs flank the round-arched gateway. Arrow slits can still be seen, some of them widened into windows in the 17th century, when the castle lost its defensive role. Inside, the second floor has a rib vault. In 1716 Jan Antoon Happart renewed the gate and had the arms of his parents, Antoon Happart and Anna Carolina de Fierlant, set above the entrance.
August Ulric Marga
In 1902 August Ulric Marga came to live in the castle. Born in Waarmaarde in 1854, he joined the army in 1872 and retired as a captain in 1892. He devoted himself to ballistics: he invented a rifle that was much sought after in the colony, and a short-range shooting system for training recruits. On his estate he made cartridges and later prefabricated chalets of wood and ‘refragor’ for the colonies. He also bought the Grooten Molen, which supplied power for his factory and for the first film shows in Diegem. He died in 1925 while working on a machine gun.
Omer Van Parijs, who worked for Marga as a joiner around 1906, remembered a huge walled estate reaching as far as the Molenstraat, with a majestic entrance gate, a much larger pond with an island and a bridge, and a luxuriously furnished castle with a monumental staircase. On the estate stood small huts where cases were filled with gunpowder for the arms factory in Wetteren. According to him Marga was a peculiar man: you were better off in his good books than on his black list.
Fire and new life
In 1927 the castle was sold to the intermunicipal company for the sanitation of the Woluwe valley; Marga's daughters then took away the coat-of-arms stone above the entrance. By royal decree of 20 February 1939 the medieval forecastle was listed as a monument. Shortly after the Second World War the house burned down through the carelessness of British soldiers on manoeuvres there; the two towers were spared.
On 8 April 1953 the municipality of Diegem bought the whole site. The rear building was rebuilt, without an upper floor, to plans by the architect Karel Roelants of Machelen. Since 1970 it has been a cultural centre, with a library and reception and exhibition rooms. Permission to restore the towers came in 1974, but it was only on 20 March 1979 that the Machelen municipal council decided to carry out the works.