There are no passages or corridors in the Sassanid palaces. The rooms for the most part open one into the other. Where this is not the case, they give upon a common meeting−ground, which is either an open court, or a large vaulted apartment. The openings are in general doorways of moderate size, but sometimes they are arches of the full width of the subordinate room or apartment. As many as seventeen or eighteen rooms have been found in a palace.