Ka'ba-ye Zartosht: Unraveling the Enigma of Iran's Ancient Structure

In the heart of the historical marvel that is Naqsh-e Rustam, adjacent to the Zangiabad village in the Marvdasht county of Fars, Iran, lies a remarkable relic of antiquity known as Ka'ba-ye Zartosht, or the Cube of Zoroaster. This rectangular stepped stone structure is a testament to the rich history of the region, where the memories of the Elamites, Achaemenids, and Sasanians converge.

An Architectural Marvel

Ka'ba-ye Zartosht stands proudly, positioned precisely 46 meters (151 feet) from the mountain, serving as a symmetrical counterpart to Darius II's mausoleum. Constructed from white limestone, it reaches a towering height of approximately 12 meters (39 feet), or 14.12 meters (46.3 feet) when factoring in the triple-tiered staircase. Each side of its base spans around 7.30 meters (24.0 feet). A solitary entrance door beckons visitors, leading to an inner chamber accessible via a thirty-stair stone staircase.

What distinguishes this architectural wonder is the meticulous craftsmanship of its builders. Rectangular stone blocks, devoid of any mortar, are stacked atop one another, seamlessly held together by dovetail joints. The stones vary in size, ranging from 0.48 by 2.10 by 2.90 meters (1 ft 7 in by 6 ft 11 in by 9 ft 6 in) to 0.56 by 1.08 by 1.10 meters (1 ft 10 in by 3 ft 7 in by 3 ft 7 in). This intricate construction undoubtedly harks back to the Achaemenid era, a conclusion supported by compelling evidence.

A Glimpse into the Past

Several factors contribute to the dating of Ka'ba-ye Zartosht to the early Achaemenid era:

1. The use of black stone on a white background, a hallmark of Pasargadian architecture.
2. Dovetail joints, predominantly found during the reigns of Darius I and Xerxes I, along with stone alignment resembling primary structures at Persepolis.
3. The design of the entrance door, akin to the mausoleums of Achaemenid shahs, notably influenced by Darius I's mausoleum.
4. The masonry style, lacking mortar and order, bears resemblance to the initial stages of the Persepolis platform construction during Darius I's reign. Notably, the inscription on the lower part of Persepolis' southern wall aligns in size with the stones forming Ka'ba-ye Zartosht's ceiling.

Explorations and Observations

European travelers of the 17th century, such as Jean Chardin, Engelbert Kaempfer, and Cornelis de Bruijn, produced some of the earliest depictions of the structure. However, the first comprehensive studies and excavation reports emerged through the work of Erich Friedrich Schmidt, featuring illustrations and detailed blueprints.
In 1923, the Naqsh-e Rustam complex, including Ka'ba-ye Zartosht, underwent examination by Ernst Herzfeld. Subsequently, the Oriental Institute of the University of Chicago, led by Erich Schmidt, conducted extensive investigations from 1936 to 1939. Their findings included the discovery of the Middle Persian version of Shapur I's Great Inscription, inscribed on the structure's wall.

Debates Surrounding Its Purpose

The exact purpose of Ka'ba-ye Zartosht remains a subject of debate among archaeologists and scholars. Various theories have been proposed:

1. Some assert it to be a mausoleum.
2. Others, like Roman Ghirshman and Schmidt, suggest it was a fire temple where sacred fires were employed in religious rituals.
3. Henry Rawlinson and Walter Henning posit that it served as a treasury for religious documents and the Avesta.
4. A minority posits it as a temple dedicated to Anahita, housing the goddess's statue.
5. Heleen Sancisi Weerdenburg speculates that Darius I may have constructed it for coronation purposes.
6. Shapur Shahbazi argues it functioned as an Achaemenid mausoleum, later repurposed for storing religious documents during the Sasanian era.

A Legacy of Intrigue

Erich Friedrich Schmidt's observation underscores the enduring enigma of Ka'ba-ye Zartosht—an architectural masterpiece designed to safeguard its contents within a single, enigmatic chamber. The heavy, two-panel entrance door provides a glimpse into the ancient efforts to protect the sanctity of this structure, shrouding it in mystery for generations to come.

Ka'ba-ye Zartosht continues to be a source of fascination for historians, archaeologists, and curious travelers, inviting us to unravel the secrets of Iran's distant past.