At the beginning of the Revolution, the organ of the Saint-Denis Basilica was preserved, while the church was ransacked and its roof destroyed. The instrument was then dismantled, moved and never found. In 1836, François Debret, the architect in charge of the restoration of the basilica, designed the case for the future organ. Built by André Bouxin, the oak case with three turrets was sculpted by Blois and Bruns. Debret entrusted the mechanism to Aristide Cavaillé-Coll (1811-1899), a young organ builder. Cavaillé-Coll invented a system of lightening the keyboard which gave a softer touch and created almost 4,200 harmonic pipes.