Explore the ruins of Port-Royal-des-Champs Abbey during the 2026 Heritage Days.

Imagine a sanctuary so influential that the Sun King himself ordered every stone to be razed in a bid to erase it from the map. On 19 and 20 September 2026, the preserved site of Port-Royal des Champs, tucked in the lush Chevreuse valley in Magny-les-Hameaux in the Yvelines, lifts the veil on its fascinating past for the 43ᵉ edition of the Journées du Patrimoine. This free outdoor outing is the ideal occasion to wander among the romantic ruins, visit the national museum and soak up the unique atmosphere of this iconic Île-de-France estate.

Founded in the early 13th century, the abbey embraced the precepts of Cistercian art: austere architecture without gilding or ornament, defined by absolute geometric rigor and expansive, sober arches designed to encourage spiritual reflection. In the 17th century, the site became the beating heart of the Jansenism, a demanding theological and moral doctrine that espouses uncompromising piety and the notion of “effective divine grace.”

Great minds retreat there to ponder or study. The playwright Jean Racine spends his formative years there beside the famed “Petites Écoles,” while the philosopher and mathematician Blaise Pascal champions the community by quietly drafting his famous Provinciales.

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This independence of mind eventually riled the royal authorities. Seeing this intellectual hub as a direct threat to his absolute power and to the unity of the Church, Louis XIV ordered the expulsion of the last nuns in 1709, followed by the complete demolition of the abbey buildings between 1711 and 1713.

Contemporary accounts say the king insisted the land be thoroughly plowed and sown to erase any trace of the monastery. Some even claim that manuscript treasures and relics were secretly buried in the surrounding woods by the faithful before the estate was razed.

The 2026 Heritage Days program at the ruins of Port-Royal-des-Champs Abbey

• Guided tour of the ruins site of Port-Royal-des-Champs Abbey, including the 1891 Oratory

  Guided tour of the ruins site at 2:00 p.m. on Saturday the 19th and Sunday the 20th of September. The 1891 Oratory will be open for a special viewing, marking it as the first museum dedicated to Jansenism.

  Participation terms: Free | No reservation required

  Hours: Saturday, September 19, 2026 — 10:30 AM–6:00 PM | Sunday, September 20, 2026 — 10:30 AM–6:00 PM

• Beekeeping workshop

  Educational workshop hosted by the Abbey Apiary Association.

  Participation requirements: Free of charge

  Hours: Saturday, September 19, 2026 — 11:00 AM to 5:00 PM | Sunday, September 20, 2026 — 11:00 AM to 5:00 PM

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