In 1734 Voltaire is under threat of imprisonment following the publication of the "Lettres anglaises", sharply critical of French institutions.
His friend, the Marquise du Châtelet, née Emilie de Breteuil, gives him refuge in Cirey.
Born in 1706, twelve years younger than Voltaire, Emilie du Châtelet is gifted with remarkable intelligence.
She received an outstanding education, a rarity for a young girl in the 18th century. She possesses a solid understanding of physics, astronomy and astrophysics, and is beginning the of study mathematics.
Voltaire and the Marquise du Châtelet lived a veritable romantic passion in Cirey.
Referring to Émilie, Voltaire writes to a friend:
"Everything about her is noble, her attitude, her tastes, the style of her letters, her way of speaking, her politeness... Her conversation is pleasant and interesting."
Though sensitive to Emilie’s charms, the philosopher very quickly succumbs to those of the house. He undertakes significant restoration works, enlarges the château and has an imposing door sculpted, dedicated to the arts and sciences.
For Voltaire, the stay in Cirey is a period of intense literary output. In order to fulfil his passion, the philosopher builds a small theatre still visible today.
Voltaire and Emilie host many of the great figures in the scientific world. It is at Cirey that Madame du Châtelet translated and commented Newton’s famous Mathematical Principles of Natural Philosophy, the strongest scientific work of the period, dealing with gravitation so rightly called “universal”.
Although, over time, the romantic passion that binds them gives way to a friendship, Voltaire and Emilie never leave each other. Only the death of the Marquise in 1749 separates them.
Voltaire, very affected by her disappearance, leaves Cirey, his "earthly paradise”.