King Louis XV vowed in 1744 that if he recovered from his illness he would replace the ruined church of the Abbey of St Genevieve with an edifice worthy of the patron saint of Paris. He did recover, and entrusted Abel-François Poisson, marquis de Marigny with the fulfillment of his vow. In 1755, Marigny commissioned Jacques-Germain Soufflot to design the church, with construction beginning two years later.