Facing the cliffs of Naqsh-i-Rustam and their royal tombs stands the Ka'bah-i-Zardusht, which was probably built in the first half of the sixth century B.C. This square tower, forty-one feet high and twenty-four feet square, rises from a terraced platform. It is constructed of large blocks of limestone joined without mortar and held together by means of iron cramps. Stone steps lead up to the entrance, which opens into a large single room. Scholarly opinions about the purpose of the Ka'bah are divided. Some think that it was the burial place of an early Achaemenian king; others, that it was later used as a fire temple of the goddess Anahita, where the Sasanian kings were crowned.
In 1936 excavations of the tower uncovered a Sasanian trilingual inscription, in Middle Persian, Greek, and Parthian, that Shapur I had had engraved on three sides of the structure. In it he described his three victorious campaigns against Rome (between 243 and 260 A.D.). Scholars today accept this description as historical fact. It is also an important record, for this was the last time that Greek was used in Iranian inscriptions.
- Naqsh-i-Rustam, The Tower, Known as the Ka'bah-i-Zardusht, Near the End of the Excavation, View from the Top of the Cliff, P 61069
- Naqsh-i-Rustam, Tower at the Start of the Excavation, P 59020
- Naqsh-i-Rustam, Excavation of the Stairs of the Tower, P 60746
- Naqsh-i-Rustam, Tower Opposite the Cliff, after Excavation, Direction of View, SE, P 61112
- Naqsh-i-Rustam, Tower Opposite the Cliff, E Face, Upper Portion, P 61081
- Naqsh-i-Rustam, Tower Opposite the Cliff, N Face, P 61079
- Naqsh-i-Rustam, Excavation of the Tower with the Middle Persian Inscription of Shapur I on E Wall, P 57206
- Naqsh-i-Rustam, Dr. George Cameron Reading the Middle Persian Inscription on E Wall of the Tower, P 60787
- Naqsh-i-Rustam, Part of the Parthian Version of the Inscription of Shapur I on W Wall of the Tower, PS la
- Naqsh-i-Rustam, Two Fire Altars, P 57194