Nestled in Jouars-Pontchartrain, in the heart of the Yvelines, the Ferme d’Ithe is set to reveal its forgotten treasures. The event is part of the National Architecture Days which run from the 16 to 18 October 2026. Launched by the Ministry of Culture, this initiative spotlights both contemporary creations and historic buildings that shape our landscapes, in Paris and across Île-de-France.
Far from the simple farmstead of days gone by, this rural site captivates with its layered history. Established in the 12th century as a monastic barn linked to the prestigious abbaye des Vaux-de-Cernay, the Ferme d’Ithe was originally built to the strict principles of Cistercian architecture: austere lines, a rigorous utilitarian logic, and an unwavering pursuit of material sobriety, with no superfluous ornamentation.
The site, however, may conceal foundations far older. Local legend holds that underground galleries still connect the farm to nearby villages, while the estate is said to stand directly atop the ruins of the ancient Gallo-Roman city of Diodurum. If archaeologists confirm the presence of a major trading crossroads beneath the surrounding soil, certain vaulted chambers attributed to that Roman era would, in fact, bear marks of successive medieval alterations.
Today, the Association for the Preservation of the Ithe Farm (APSFI) and archaeologists are hard at work rehabilitating this rare witness to the medieval economy of Île-de-France. Between a disused chapel, a tithe barn, and a remodeled dwelling, the stones tell the daily life of the lay brothers and the transformation of the rural world over the centuries.
The site’s mission is now clear: to pass on this traditional building craft, safeguard a fragile vernacular ensemble, and bridge the Gallo-Roman past with Île-de-France’s rural history. A refreshing stop to view our old stones with a new perspective.
Getting Started with Plastering
Making plaster cornices and decorative mouldings
Participation terms: Free | No reservation required
Hours: Saturday, October 17, 2026 – 10:00 to 18:00
Gemstone Cutting
Introduction to stone carving with our volunteer, an apprentice stonemason
Participation requirements: Free | No reservation required
Schedule: Saturday, October 17, 2026 — 10:00 AM–6:00 PM
Raw bricks
Production of unfired clay bricks
Participation terms: Free | No reservation required
Schedule: Saturday, October 17, 2026 — 10:00–18:00
Reconstruction of a Protohistoric Building
Our volunteers are building a protohistoric building using the era's techniques and materials (stone and sun-dried bricks).
Participation terms: Free | No reservation required
Hours: Saturday, October 17, 2026 — 10:00 AM to 6:00 PM
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Dates and Opening Time
On October 17, 2026
Location
The Ithe Farm
Route de Bazoches
78490 Tremblay sur Mauldre (Le)
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