It was not enough for Léonce Reynaud – a diocesan architect connected with the Monuments Historiques – to theorise about Cordouan. Early in the Second Empire, he initiated an extensive restoration programme that had a profound and lasting effect on the building. It was carried out by Pairier, a senior Ponts et Chausséesengineer from Gironde. Even though the complete documentation has not come down to us, we can nevertheless grasp the essential of the work that was undertaken. Stones in the shaft that had been eroded by salt were replaced, which in turn brought out elements of the royal decor. The religious aspects of the building were also carefully attended to, at a time when the imperial power sought to attract the support of the Church. A full restoration of the chapel’s marble, stained-glass windows and altar was undertaken so that services could be held there, and to accommodate sailors’ prayers. Reynaud and Pairier were also responsible for the renovation of the lighthouse keepers' quarters and technical areas built into the crown that encircles the lighthouse. The lighthouse’s current roof, as well as the so-called King’s Lieutenant's Chamber, date from this period.