The Palace Guard Room, located on the axis of the Ceremonial Façade and the upper Gardens, the parterre, served as the noble entranceway to the Palace also known as the Body of Guards. This opens directly onto the Hanging Garden and was the place where the halberdiers stood guard.

The exterior doorway was watched over by two sculptures by John Cheere portraying the two Greek gods, Mars – god of war and youth and symbolising masculine strength – and his sister Minerva who, in contrast to Mars, represents the victory of reason and justice over impulse.

On the wall, there are portraits of the founding couple, Maria I and Pedro III.