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Bois-Seigneur-Isaac Castle Travel Guide

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Castle of Bois-Seigneur-Isaac (©
Château de Bois-Seigneur-Isaac.


Property of the Barons Snoy since 1810, this white 18th-century castle is one of the handsomest in the Walloon Brabant. It is completed by a formal French garden and a 7-hectare (17-acre) English-style park boasting over 50 multi-centennial trees.


Bois-Seigneur-Isaac (literally "Lord Isaac's Wood") owes its name to Isaac of Valenciennes, a member of the House of Hainault, who planted a wood in the area in the 11th century.

The first castle probably dates from the 12th century, and was destined to protect this enclave of the County of Hainault from its mighty neighbour, the Duchy of Brabant. The castle successively belonged to the families of Huldenberg, Dave, and Sainte-Aldegonde, until the end of the 17th century, when the last Countess of Sainte-Aldegonde (née Agnes of Dave) died. Unfortunately, the laws in Hainault and Brabant were contradictory in matters of inheritance, leading to a grave and ruinous conflict between her heirs.

In 1712, the seigneury and castle were eventually sold to Sir Antoine de Belhomme, Receiver General of the Aids and Subsidies of the County of Hainaut. He and his wife, née Marie-Thérèse Rouillon de Castaigne, commissioned architect Hannotaux to transform the medieval fortress into a residential castle. The new castle was built between 1730 and 1740 in the French classical style, on the foundations of the old one.

In 1810, the sole heir of Bois-Seigneur-Isaac, Joséphine Cornet de Grez, great-grand-daughter of Antoine and Marie-Thérèse, marries Baron Idesbalde-François Snoy et d’Oppuers. The castle then passes to the senior line of the Snoy family, who make it their principal residence. Bois-Seigneur-Isaac is now at the fifth generation of Snoy since 1810. The most illustrious member of the family was probably Count Jean-Charles Snoy et d’Oppuers (1907-1991), who as Secretary General of the Ministry of Economic Affairs, negociated and signed the Treaty of Rome (1957) for Belgium. His widow (née Countess Nathalie d'Alcantara), his son (Baron Bernard Snoy), his daughter-in-law (née Christine de Weck), and his grand-children, are the present occupants of the castle.

Opening Hours & Admission

The Castle of Bois-Seigneur-Isaac is only open three Sundays in Summer (usually late June to early July), and on Heritage Days (journées du patrimoine, usually the second weekend of September), between 2 pm and 6 pm. Admission is 7 € for adults, or 5 € for children between 6 and 14 years old. It is free on Heritage Days. Visits are only on guided tours and last from 30 to 50 min.

The castle can also be visited at other times of the year on request for groups of minimum 15 people (7 € per person).

Bois-Seigneur-Isaac can also be rented for receptions, weddings, seminars and various types of events (=> see official website).

How to get there

The castle is located opposite the church in the village of Bois-Seigneur-Isaac (municipality of Braine l'Alleud), between Waterloo and Nivelles.

By car, Bois-Seigneur-Isaac is close to the junction between the Ring of Brussels (R0) and the E19 motorway towards Mons and Lille. There are three possible approaches. If you are coming from the East Ring, take exit 23 for Ophain, follow the road to Bois-Seigneur-Isaac, and turn right toward Ittre at the first junction inside the village. Coming from the West Ring, take the exit for Ittre (no number, just at the junction between the R0 and E19), and follow the road toward Nivelles. Coming south from the E19, take exit 18 for Nivelles-Nord, and follow the road toward Ittre.

Using public transports, take the train to Braine l'Alleud (20min from Brussels-Central), from where buses regularily make the connection to Bois-Seigneur-Isaac (15min).

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