Archeologists believe that an ancient fortress in a valley in Iraqi Kurdistan may be the lost city of Natounia, based on the discovery of intricately carved rock reliefs depicting an ancient leader.

Rabana-Merquly was once part of the Parthian Empire, which ruled between 250 B.C. and A.D.224. The Parthians were enemies of the Roman Empire for over 250 years. The research suggests that the fortress was a regional center of the empire.

The two entrances to the settlement were discovered by an international team of archeologists. According to researchers, the king of Adiabene is depicted in the matching reliefs.

A photo (top) of Mount Piramagrun, highlighting the Rabana and Merquly settlements, and a topography (bottom) of Rabana-Merquly.

A photo (top) of Mount Piramagrun, highlighting the Rabana and Merquly settlements, and a topography (bottom) of Rabana-Merquly. (Image credit: Map by M. Brown; © Rabana-Merquly Archaeological Project; Antiquity Journal Ltd.)

Michael Brown, a researcher at the Institute of Prehistory, Protohistory and Near-Eastern, said that the fortress was built by the ruling dynasty of Adiabene close to the kingdom's eastern border. The twin rock reliefs are rare examples of monuments of rulers from the Parthian period and allow us to link the fortress with those who built it.

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He said that the reliefs were designed to make a political statement and can be characterized as ancient propaganda.

There is a lost palace of a once-mighty empire.

According to a statement, several coins dating from the first century B.C. have depictions of the existence of Natounia.

The inscription on the rare coins of the city of Natounia states that it is on the Kapros. The city was sometimes referred to as Natounia.

A) Rabana ‘sanctuary’; B) staircase; C) iron arrowheads; D) altar

Here we see the (A) Rabana 'sanctuary'; (B) a staircase at the site; (C) iron arrowheads; and (D) altar (scales = 1 meter) (Image credit: © Rabana-Merquly Archaeological Project; Antiquity Journal Ltd.)

Researchers used drones to explore the 2.5 mile (4 kilometer) fortifications along with two nearby settlements, Rabana and Merquly, of which the site is named.

A) Merquly rock-relief; B) Rabana rock-relief; C) statue from Hatra of King ʾtlw/Attalos of Adiabene

These images show the (A) Merquly rock-relief; (B) Rabana rock-relief; and (C) a statue from Hatra of King 'tlw/Attalos of Adiabene. (Image credit: Illustrations by M. Brown; © Rabana-Merquly Archaeological Project; Antiquity Journal Ltd.)

"Rabana-Merquly is the largest and most impressive site of the Parthian era in the region, and the only one with royal iconography, so it's the best candidate for being Natounia," Brown said. The fortifications can be seen as an extension of the surrounding landscape. Lord of the Rings is a real life Helm's Deep.

Here we see a coin of Natounia.

The reverse side of a coin of Natounia.  (Image credit: Photograph © The Trustees of the British Museum. Shared under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) license).)

Through its relations with Rome, India and Han China, the Parthian Empire helped develop the development of globalization. He said that the fortress probably played an important role in managing the relations.

The fortress was abandoned by the Parthians relatively soon after it was constructed. The fortress wasn't used for a long time during the Parthian era. Brown said it would probably take no more than 100 years.

Brown and his team found a large waterfall in the valley, which he calls aseasonal phenomena, since it appears only after a heavy rain.

Rabana's Parthian-era inhabitants may have had religious significance to it. The Iranian water-goddess Anahita could be associated with this. The small altar is most likely for fire.

The findings will be published in a journal on Wednesday.

It was originally published on Live Science