A lost royal city where worshippers prayed to a water goddess 2,000 years ago and whose existence was known only from ancient coins may have been found by scientists.

Precious little is known about Natounia, believed to have been part of the Parthian Empire and one of many cities in the Middle East that are lost to antiquity.

But now researchers think they know where it is – on the site of an ancient fortress in modern Iraqi Kurdistan that has been the subject of study for a decade.

The intriguing hypothesis is the result of work by team of archaeologists led by Dr Michael Brown, a researcher at Heidelberg University in Germany working with Iraqi colleagues.

According to their research, published in the journal Antiquity, the mountain fortress of Rabana-Merquly was once a major regional centre of the Parthian Empire, a sprawling power which covered parts of Iran and Mesopotamia approximately 2,000 years ago.

Situated on the flanks of Mount Piramagrun in the Zagros Mountains, the settlement boasted kilometres-long fortifications but also two smaller settlements for which it is named.

Because of its position high up on a mountain, mapping the site was possible only with drones.

Multiple excavation campaigns were conducted between 2009 and 2022, allowing the international team of researchers to study the archaeological remains on site.

Much of the fortress has been astonishingly well-preserved and include structures that suggest a military use.

Also found was a sanctuary-style complex where heavy rains would produce a waterfall into a monumental stone structure, with a staircase carved into the bedrock.

Researchers say the prominence of water suggests a cultic link to the Zoroastrian Iranian goddess Anahita, who was venerated as a divinity of “the Waters”.

What is more, the research team suspect that Rabana-Merquly may be the lost royal city of Natounia.

Until now, the existence of Natounia on the Kapros, or alternatively as Natounissarokerta, had only been documented on seven bronze coins dating from the first century BC.

According to one scientific interpretation, the place name Natounissarokerta is composed of the royal name Natounissar, the founder of the Adiabene royal dynasty, and the Parthian word for moat or fortification.

“This description could apply to Rabana-Merquly,” Dr Brown says.

Dr Brown believes the intriguing wall reliefs at the entrance to the fortress may depict the city’s founder, either Natounissar or a direct descendant.

He says the relief resembles a likeness of a king that was found approximately 230 kilometres away in Hatra, a location rich in finds from the Parthian era

“The considerable effort that must have gone into planning, building, and maintaining a fortress of this size points to governmental activities,” he added.

The study of Rabana-Merquly is part of wider investigation of Parthian settlements and society in the Zagros highlands on both sides of the Iran-Iraq border.

During the latest excavations Dr Brown collaborated with colleagues from the Directorate of Antiquities in Sulaymaniyah, a city in the autonomous region of Iraqi Kurdistan.

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