The room now known in La Rochelle as the Oratory has been considerably modified with time. First, it was the chapel of the convent of the Sœurs blanches de Sainte-Marguerite – White sisters of Saint Margaret- 15^th century portal on the rue du Collège -, but was left by the nuns when religious unrest began. Then the building was used as a hospital for the wounded during the 1573 siege, and finally as an artillery store. The Catholics used part of it at times when they were allowed to celebrate mass.

In 1567, the provincial synod of Saintonge, Aunis and Angoumois was held in the church which was then returned to the Catholics after the Edict of Nantes. The Oratory congregation took over the building and also built new premises.

When political-religious unrest flared up again upon Henri IV’s death, the Oratorians were expelled from the city and protestant preaching was resumed at Saint Margaret in 1621. Richelieu solemnly celebrated mass  here after La Rochelle surrendered in 1628.