Excavations in the mountains of modern Iraqi Kurdistan have uncovered the remains of a large fortress that was once one of the major regional centres of the Parthian Empire – which controlled parts of Iran and Mesopotamia from the 2nd century BC to the 2nd century AD. This may even be the site of a lost royal city.
Archaeological investigations have been taking place at the site, known as Rabana-Merquly, since 2009, with the most-recent phase of work carried out by an international team led by Dr Michael Brown, from Heidelberg University, between 2017 and 2022. Occupation of the fortress appears to have been relatively short-lived, with the main phase of activity probably dating to the 1st century BC, although there is also evidence of some later reoccupation. However, the site is exceptionally well preserved, offering an almost complete picture of the large, fortified settlement.

The stone fortress sits on the side of Mount Piramagrun in the Zagros Mountains, and is composed of c.4km of fortification walls, which, together with the natural defensive qualities of the landscape, create a large, enclosed area, encircling two neighbouring settlements – one in the Rabana Valley and one on the Merquly Plateau – as well as several dispersed structures. The site is at a key intersection between highland and lowland zones, with strategic views over the surrounding landscape. The site probably played an important role in regulating interactions between groups in the area and maintaining control, as well as identifying and countering approaching threats, and providing shelter for nearby communities when necessary. A number of rectangular buildings identified within the enclosure are believed to have been barracks, further supporting the military function of the site.

Archaeologists also found evidence of a religious complex at Rabana-Merquly, with steps carved into the bedrock leading down to a small rock-cut altar. After heavy rains or snowmelt, this point where the wadi enters the valley becomes the site of a temporary waterfall, leading to suggestions that the sanctuary was dedicated to the Zoroastrian Iranian deity Anahita, goddess of water and fertility.
Perhaps the most-significant discovery, however, was two reliefs carved into the rock at the entrance of the fortress, each depicting a life-sized ruler wearing ceremonial headgear. The ruler is unnamed, but Rabana-Merquly is located near the border of the vassal kingdom of Adiabene, which was under the control of the Parthian Empire at the time of the site’s occupation, and researchers believe that the reliefs could show either Natounissar – the founder of the Adiabene royal dynasty – or one of his direct descendants.
These reliefs, combined with the site’s location near the Lower Zab River (known in antiquity as the Kapros) have led various local and foreign archaeologists to suggest that Rabana-Merquly could be the royal city known as Natounia on the Kapros or Natounissarokerta, which is mentioned on several coins from the 1st century BC. It has been proposed that Natounissarokerta is a combination of the name Natounissar with the Parthian word for moat or fortification, which would match the description of Rabana-Merquly. Only one other Parthian-era settlement of comparable scale is known within the Lower Zab watershed, but Rabana-Merquly is by far the best contender for the lost city, although of course we cannot say for certain.
The research has been published in Antiquity (https://doi.org/10.15184/aqy.2022.74).