76 ornate helmets form the keystones of the arched windows on the ground floor of the Zeughaus’ exterior façade. They often form groups of three viewed from the front and the two sides. The arrangement of the nineteen keystones within each façade is symmetrical, starting from the central axis.
The helmets with their mighty feathered crests, under which mythical creatures such as dragons and sphinxes as well as lions and eagles are hiding, represent the trophies of victory. All keystones of the exterior façade can be attributed to the sculptor and architect Andreas Schlüter and his workshop. They were created in 1696 and are among Schlüter's earliest works.
On the north side, Schlüter designed the keystones of the central and side entrances in a special way. The ones above the two side entrances deserve special attention. They show Medusa's head entwined with snakes — the symbol of terror. In Greek mythology it was Medusa whose gaze turned anyone she looked at to stone. The hero Perseus was able to behead her. From that point on, he used her severed head as a weapon. What is special about the depiction here is that Andreas Schlüter doesn’t depict Medusa as a grotesque horror like other sculptors before him, but as a human.
The twenty-two heads of dying warriors in the inner courtyard of the Zeughaus correspond to the seventy-eight helmets on the exterior facade.
