The name designates the construction located right behind Liberty Gate, at the feet of the Heredia twin towers. As the blazons on the building’s façade suggest, the Arsenal was commissioned by Grand Master De Milly (1454-1461) and refurbished with the care of Grand Master Orsini (1467-1476), in the light of the new circumstances created by the advent of powder.
In the aftermath of the completion, in 1489, of the construction of the “New Hospital of the Knights”, the premises that until then housed the knightly infirmary (Old Hospital), across from the Inn of the Tongue of Auvergne, were decommissioned, in favour of the Arsenal. The premises are estimated to have harboured a canon foundry. Tradition has it that Knight Dieudonné de Gozon – later to become a Grand Master of the Order, was on these very premises to be found momentarily under the weight of the carcass of the dragon he had just annihilated.