The Capitouls of Toulouse embarked on the construction of the original building in 1190, to provide a seat for the government of a province growing in wealth and influence. The name "Capitole" referred not only to the Roman Capitol but also to the capitulum which was the chapter of the governing magistrates.
Viollet-le-Duc built a bell tower typical of the style of northern France on top of the donjon of the building. It was in this donjon that Jean Calas, a Protestant victim of a religiously biased trial, was interrogated. Only the Henri IV courtyard and gate survive from the original medieval buildings. It was in this courtyard that the Duke de Montmorency was decapitated after his rebellion against Cardinal Richelieu.