The Gothic facade of the Saint-Denis basilica dates from the 12th century. But the clock of the stone rose window was only installed in the 16th century. In 1827, its mechanism broke down. The architect in charge of the restoration of the basilica, François Debret, decided to replace it with a contemporary creation of 4.5 meters in diameter ordered from Wagner, the king’s clockmaker. The new clock, with Roman numerals in enamelled Volvic stone and curious snake-shaped hands, was installed in 1840. Completely rehabilitated in 2015, the clock is now equipped with a motor that winds the mechanism.