An arms depot was later built above the Porte Saint-Antoine, all making the Bastille part of a major military centre.

During the 1550s, Henry II became concerned about the possibility of an attack on Paris by England or the Holy Roman Empire, and strengthened the defences of the Bastille in response. The southern gateway into the Bastille became the principal entrance to the castle in 1553, the other three gateways being closed. A bastion,