On this day in 1879, Eugène Viollet-le-Duc died in Lausanne, aged sixty-five. He had spent his working life on Notre-Dame de Paris, on Vézelay, on the walls of Carcassonne, on Saint-Denis and Mont Saint-Michel — buildings he read, argued with, and in places completed in his own hand.

Look at one detail. Around the base of the spire he designed for Notre-Dame stood copper figures, the twelve apostles in four groups of three, all of them facing outward over the city. All but one. Saint Thomas, patron of architects, was turned inward and upward, toward the spire itself, and the sculptor Geoffroy-Dechaume gave him Viollet-le-Duc's face. A man in green copper, holding a ruler, looking up at his own work. It is the quietest signature I know on a building that size.

The face is the part people remember. I think about the hands. The stone came from quarries and passed through masons who cut crockets and gargoyle throats they would never see from the ground, apprentices who dressed blocks, carpenters in the roof timbers, labourers who shifted the scaffolding week after week. Their names are mostly gone from the record. Their tool marks are not. If you stand close to the masonry at Vézelay you can still read the direction a chisel travelled, and the hand behind it, unhurried.