Khorezm Fortresses: Desert Archaeology between the Amu Darya and the Silk Road

On the right bank of the lower Amu Darya, where irrigated fields give way to the red sands of the Kyzylkum, the ruins of walled towns and hilltop castles stand above the plain like weathered sandcastles. The Khorezm fortresses were built of mud brick over more than a thousand years, and they are easy to admire as silhouettes. They make more sense read as a system: a line of strongholds, palaces and farm settlements that existed only because canals carried river water into the desert, and that fell silent when the water and the power behind it moved elsewhere. On Day 5 of our small group tour through Uzbekistan, Turkmenistan, Kyrgyzstan and Kazakhstan, the group stops at two of them, Toprak Kala and Ayaz Kala, on the road from Nukus to Khiva.

The Khorezm fortresses in their landscape

Khorezm, the Chorasmia of Greek and Persian sources, is the oasis country of the Amu Darya delta, south of the Aral Sea. Today it is divided between Uzbekistan’s Khorezm Region, the autonomous Republic of Karakalpakstan and northern Turkmenistan. On our four-country journey through the Stans it is the historical landscape that follows Tashkent, and the fortresses are its ancient layer. Most of the sites visitors see lie on the river’s right bank in Karakalpakstan, in and around a district called Ellikqala, a name usually translated as “fifty fortresses”.

The number is a figure of speech, but the density is real. In 2008 Uzbekistan placed eight of the sites on UNESCO’s Tentative List under the title “Desert Castles of Ancient Khorezm”: Toprak Kala, Ayaz Kala, Koy-Krylgan Kala, Big Guldursun, Pil Kala, Anka Kala, Kurgashin Kala and Djanbas Kala. They range from a round temple-like building to a palace city and a medieval frontier stronghold, and they span more than fifteen centuries. For broader orientation to the country, our guide to Uzbekistan’s history and must-see sites sets the scene; this article stays with the desert.

Modern knowledge of the sites rests largely on the Khorezm Archaeological-Ethnographic Expedition led by the Soviet archaeologist Sergei Tolstov. Encyclopaedia Iranica records that Tolstov discovered Toprak Kala in 1938 and that its excavation ran to twenty-eight field seasons; the World Monuments Fund notes that the Ayaz Kala fortresses were excavated in the 1940s after some 1,300 years of abandonment. Among those who came to Karakalpakstan with the expedition in the 1950s was the painter Igor Savitsky, whose museum in Nukus also houses a large archaeological collection.

Water first: the Amu Darya and the canals of ancient Khorezm

The Amu Darya, the Oxus of the Greeks, is about 2,500 kilometres long, according to Encyclopaedia Iranica, and until the later twentieth century its lower course spread into a broad delta before reaching the Aral Sea. Rain in this part of Central Asia is scant, so every field in Khorezm has always depended on diverting the river. That single fact explains where the fortresses stand. They sit on the margins of land that canals could reach, facing the desert beyond.

The archaeologist Yuri Rapoport, writing in Encyclopaedia Iranica, traces the canals back to the sixth and fifth centuries BC, when the first large channels were 10 to 15 kilometres long. In later centuries the trunk canals on the right bank grew two or three times longer, some reaching 300 kilometres. A network on that scale demanded labour, maintenance and someone with the authority to organise both, and the walled settlements and strongholds are the visible trace of that authority. They protected farms, stored harvests, housed garrisons and, in the grander cases, displayed royal power.

The same dependence made the system fragile. When canal heads silted up, when the river shifted its channels or when a ruler could no longer command the labour to keep water flowing, whole districts dried out. Iranica’s entry on the Amu Darya notes that silting of riverbeds led to the abandonment of the old capital Kath and to the repeated desertion of Gurganj, the city now known as Konye-Urgench. The desert fortresses are what remains where that cycle ended for good. The river’s final destination has its own story in our article on the Aral Sea and the changing landscape of Karakalpakstan.

A kingdom on the frontier of empires

Khorezm entered written history as a province of the Achaemenid Persian empire. Iranica notes that it appears in Darius I’s Bisotun inscription among the countries he inherited, and that Herodotus placed the Chorasmians in a tax district alongside the Parthians, Sogdians and Arians. From about the beginning of the fourth century BC, probably through Achaemenid scribes, Khorezm adopted the Aramaic script to write its own Iranian language; by the later fourth century the kingdom had slipped out of Persian control.

Independence brought its own pressures. Nomadic peoples of the steppe lay to the north and east, and Iranica describes the destruction by fire of the round temple-fortress of Koy-Krylgan Kala in the second century BC, probably during movements of steppe peoples. Khorezm’s rulers struck their own silver coins, and Rapoport argues that this continuous local minting tells against the idea that the kingdom was ever absorbed by the Kushan empire to the south. The kings also kept their own calendar, the Khorezmian era, which Iranica dates from the 30s or 40s AD and which stayed in use for about eight centuries.

Toprak Kala: a planned palace city

Toprak Kala is less a fort than a planned royal town. Rapoport suggests that Artav, the second king of the new independent dynasty, began building it. UNESCO’s Tentative List dates the palace complex to the first to fourth centuries AD, and the town itself was lived in until the sixth century. The settlement is a rectangle of about 500 by 350 metres, enclosed by walls 8 to 9 metres high with square towers. A single central street, about 9 metres wide, ran through the town from the fortified entrance to the citadel.

Above the town rose the High Palace, built of mud brick in the form of a truncated pyramid. Around a hundred rooms survive in part, and the tourism authority describes ceremonial halls decorated with wall paintings and painted clay reliefs. In the room known as the King’s Hall stood large sculptures of 23 Khorezmian rulers, a gallery of dynastic memory set in a building meant to impress. Other halls, by the same account, carried reliefs of enthroned rulers, of deer beneath griffins, and of dancing figures, with sanctuaries and altars on the upper floor.

Toprak Kala also produced writing. The Chorasmian Online project, hosted by the University of California, Berkeley, records documents from the site on wood and leather. They are working records rather than chronicles: household lists, receipts and tally sticks, of which, the project notes, a few bear dates in the early 200s of the Chorasmian era. According to Iranica, the palaces were abandoned together, probably in connection with the founding of the Afrighid dynasty, traditionally dated to AD 305.

Ayaz Kala: three forts above the Kyzylkum

Ayaz Kala shows the other side of Khorezmian power: defence. It is not one fortress but a group of three around a hill that the regional tourism authority puts at up to 100 metres high, on the edge of the Kyzylkum Desert. The upper fort, Ayaz Kala 1, crowns the hill. UNESCO’s Tentative List gives its plan as about 182 by 152 metres, with adobe walls up to about 10 metres. The regional tourism authority dates Ayaz Kala to the fourth or third century BC and describes double walls with two-storey galleries for archers and evenly spaced loopholes, and a three-sign inscription in Khorezmian script found by the entrance.

Two more sites complete the group. Ayaz Kala 2, a smaller castle associated with the Afrighid period, was linked by a ramp to a palace at the foot of its hill that had audience halls, wall paintings and a fire temple; the tourism authority reports coins of the Afrighid king Bravik from the palace and says it was destroyed by two successive fires. Iranica cites early work on the Ayaz Kala palace complex as evidence that monumental architecture and wall painting remained vital in Khorezm in the fifth to seventh centuries. The third, Ayaz Kala 3, is a large enclosure with double walls and a many-roomed building in one corner, which may have served as a garrison, a ruler’s residence or a refuge for farmers. Its dating is disputed: sources place it anywhere between the fourth century BC and the Kushan period.

Local legend supplies a gentler origin. A Khorezmian king, the story goes, promised his daughter to whoever could build an impregnable fortress on the frontier; a shepherd named Ayaz set to work, the king broke his word, and the fort was left unfinished. Archaeology tells a less romantic tale of watchposts and garrisons, but the tourism authority also records the remains of farmsteads, fields and vineyards around the walls, a reminder that these forts guarded people who lived from the land below.

How long does the tour spend at the Khorezm fortresses?

The fortresses are visited on Day 5. The tour page describes a short morning visit to the Savitsky Museum in Nukus, then the road to Khiva, about 180 kilometres and four hours of travel, with stops en route to visit Toprak Kala and Ayaz Kala before arriving in Khiva in the evening. The page does not give a set time at each site, so if you want to know how long the group usually spends at each, ask a Tour Specialist.

A frontier network rather than a scatter of ruins

Seen together, the sites form a pattern. The UNESCO Tentative List describes Ayaz Kala as protecting the oasis, and the regional tourism authority describes Toprak Kala as the residence of a Khorezmian monarch before the Afrighids came to power. Between and around them were canals, fields and farmsteads, and beyond them the routes across the Kyzylkum and the steppe. Uzbekistan’s 2008 Tentative List submission notes that Anka Kala guarded a caravan route, and it describes Big Guldursun, rebuilt in the twelfth and thirteenth centuries over an older fort, as the largest boundary fortress of Khorezm.

Not every site was military. Koy-Krylgan Kala, a circular building about 90 metres across including its outer ring, was probably a cult centre and burial place; Rapoport notes that its round central tower may also have served for astronomical observation. Since the 1990s an Australian team has added to the picture. The Karakalpak-Australian Expedition, run by the University of Sydney with the Karakalpak branch of the Uzbek Academy of Sciences, has worked at Akchakhan-kala, which the university describes as a royal seat. According to a 2015 lecture summary from New York University’s Institute for the Study of the Ancient World, its main occupation dates from about the late third century BC to the late second century AD, and its wall paintings link Zoroastrian imagery with royal ritual.

How the fortresses fell silent

No single catastrophe emptied the right bank. Rapoport describes the fourth to eighth centuries AD as a period of change in Khorezm: the irrigation network shrank, pottery became cruder, and tribes from the Syr Darya region moved in. Power also moved, as the silting described above pushed the centre of Khorezm towards Gurganj, today’s Konye-Urgench, whose minarets and mausolea belong to a later, medieval Khorezm. Some forts, such as Big Guldursun, were rebuilt in the medieval period before being abandoned in their turn.

Once the canals failed, the fields reverted to desert, and the mud-brick walls began their slow slump. That same exposure is also what threatens them. The World Monuments Fund placed Ayaz Kala on its 2008 Watch, warning that the structures excavated in the 1940s, unprotected ever since, were the most at risk from natural decay, and that few measures had been put in place to protect them from visitors.

Are the Khorezm fortresses a UNESCO World Heritage Site?

They are on UNESCO’s Tentative List rather than the World Heritage List. Uzbekistan submitted the “Desert Castles of Ancient Khorezm”, including Toprak Kala and Ayaz Kala, to UNESCO’s Tentative List on 18 January 2008, which is the step before a formal nomination. Inscription on the World Heritage List itself would require a separate nomination and a decision by the World Heritage Committee.

Where can you see finds from ancient Khorezm?

Start in Nukus. The regional tourism authority describes the archaeological collection of the Savitsky Museum in Nukus as holding more than 15,000 items that trace the region from the Bronze Age through ancient Khorezm to the end of the fourteenth century, and the tour’s short visit there comes on the morning of Day 5, before the fortresses.

How physically demanding is a day at the desert fortresses?

The tour is rated Level 3, Moderate to Challenging, which the tour page defines as activities that may include up to six hours a day of continuous strenuous, moderate to fast-paced activity over varied terrain, for participants in excellent health who are extremely mobile and live an active lifestyle. The upper fort at Ayaz Kala crowns a hill that the regional tourism authority puts at up to 100 metres high. Talk to a Tour Specialist about how the day is paced, and raise any health questions with your doctor before you travel.

From the Ustyurt to Khiva: the fortresses on the Stans route

The tour approaches Khorezm from its edges before reaching its heart. On Day 3 the group drives from Nukus to the shores of the Aral Sea, stopping at Kungrad, which the tour page calls the gate town of ancient Khorezm, and crossing the Ustyurt Plateau, a stony desert plain west of the Amu Darya delta where the tour page notes caravan stops between Khiva and the Volga. After a night in a tented camp, Day 4 brings the group to Muynak and its cemetery of ships before the return to Nukus.

Day 5 is the day of the fortresses, and it is also the approach to Khiva. Coming to the walled city by way of Toprak Kala and Ayaz Kala gives the right sequence: first the ancient Khorezm of canals, palaces and frontier forts, then the later city whose khans ruled the same oasis many centuries afterwards. Day 6 is given to Khiva and its walled inner town on the Amu Darya. On Day 7 the route continues into Turkmenistan to visit Konye-Urgench, the capital of the Khorezmshahs, before an evening flight from Dashoguz to Ashgabat, Turkmenistan’s white-marble capital. In three days the route covers Khorezm from its ancient fortresses to its medieval capital.

What the desert fortresses teach

The Khorezm fortresses are not ruins in the romantic sense of a lost city waiting to be found. They are the remains of a working system, in which river water, canal labour and royal authority held a farming civilisation in place on the edge of two deserts for more than a thousand years. Stand below the walls of Ayaz Kala or look along Toprak Kala’s central street, and the logic of the place is plain: where the water went, power and people followed, and when it stopped, they left. Our answers to common questions about travelling in Uzbekistan cover the country-level practicalities.

Travelling in a small group of up to 16 travellers with an Odyssey Program Leader, you reach the fortresses after the Aral Sea and before Khiva, which is the order in which their story is easiest to follow. It is one day on a long route across four countries, and a clear lesson in how the oases of Central Asia were made.