The Dome Church, created by Jules Hardouin-Mansart on the orders of King Louis XIV, is separated from the Saint-Louis des Invalides Cathedral by a monumental window built in the 19th century. Built in the shape of a Greek cross inscribed in a square plan, the church has an ingenious system of interlocking domes that render invisible the numerous windows pierced on the second level of the drum. The lead roofing on the ovoid oak frame is decorated with gold leaf relief. The construction of the Dome was completed in 1708, 27 years after the laying of the foundation stone.