On the high plains of Zanjan rises one of the largest brick domes ever built — a turquoise vault forty-eight metres tall, visible across the steppe long before you reach it. A Mongol sultan raised it seven hundred years ago, and he did not build it for himself. Oljaitu, a great-great-grandson of Genghis Khan who passed through five faiths in a single lifetime, built this colossus to hold the bodies of the Shia Imams — to make his desert capital a new Najaf, a new Karbala, the pilgrimage heart of the Shia world. The bodies never came. And so the greatest mausoleum of Mongol Persia, built for the holiest of others, became instead the tomb of the man who dreamed it.
Drive south-east from the city of Zanjan, across the high grasslands of north-western Iran, and you see it long before you arrive: a single vast dome, sheathed in turquoise, floating above a small town on the plain. This is the Dome of Soltaniyeh (گنبد سلطانیه) — and for all its serene beauty, it is one of the boldest and strangest monuments in the Islamic world, a structure built for a purpose it never fulfilled, by a ruler who is among the most extraordinary figures of medieval Iran.
The scale alone would earn it fame. Rising about forty-eight metres, it is the third-largest masonry dome on earth — surpassed only by the dome of Florence Cathedral and the Hagia Sophia in Istanbul. More than that, it is the earliest surviving double-shelled dome: an inner and an outer shell working together, a structural breakthrough that let its builders raise so enormous a vault, and one that would echo down the centuries of Islamic architecture. Scholars have traced its influence as far as the Taj Mahal. It was built in just a decade, from 1302 to 1312, by a master named Sayyid Ali Shah with three thousand workers, under the eye of the great vizier and historian Rashid al-Din Hamadani.
It was the crown of a lost city. Soltaniyeh — “the Imperial” — was the new capital of the Ilkhanid dynasty, the Mongol state that ruled Iran after the conquests of Hulagu, grandson of Genghis Khan. Begun on the Qongqur-Oleng plains under Oljaitu's predecessors and completed by him around 1306, it was a planned imperial city of palaces, mosques, markets and a great citadel, ringed by a moat some thirty metres wide. At its heart stood this dome. And when Oljaitu died and the capital drifted back to Tabriz, the city faded — until today almost nothing of Soltaniyeh survives but the dome, standing alone on the plain like the last word of a sentence the rest of which has been erased.
To understand why it was built, and why it stands half-empty of its own meaning, you have to know the man who raised it — a Mongol prince who could not decide what to believe, and who poured that restless search into stone.
The dome stands in the town of Soltaniyeh, about 40 km south-east of Zanjan and just off the Zanjan–Qazvin road, roughly three hours north-west of Tehran. It is unmissable — visible across the plain from far off.
The man who built Soltaniyeh was born around 1282, a Mongol prince of the house of Genghis Khan, and his life was a journey through the religions of his age. His mother was a Christian, and he was baptised in infancy with the name Nicholas, after the pope. He was raised amid the shamanism of his Mongol forefathers. In his youth he turned to Buddhism. Then, with his brother Ghazan, he converted to Sunni Islam as the Ilkhanid state itself embraced the faith of the land it ruled. And finally, around 1310, wearied by the quarrels of the Sunni schools and moved by great Shia theologians such as Allamah al-Hilli, he converted a last time — to Shia Islam — and took the name by which Iran remembers him: Mohammad Khodabandeh, “Mohammad, the servant of God.”
No ruler of Iran ever travelled so far in search of belief. And Oljaitu was no mere collector of creeds — he was a serious and consequential king. He completed the reforms of his brother Ghazan, corresponded with the kings of Europe about a grand alliance against the Mamluks, held open theological debates at his court, and was the first ruler to make Twelver Shiism the official faith of Iran, minting coins and reading the sermon in the names of the Shia Imams. It is a role Iran would take up again, permanently, two centuries later under the Safavids — but Oljaitu was there first.
And into this last, deepest conversion he poured his greatest work. Having found, as he believed, the true faith, the Mongol khan set out to build it a monument to outshine anything in the land — and to give his new capital a holiness that would draw the whole Shia world to the plains of Zanjan.
Oljaitu's plan was breathtaking in its boldness. He would build, at Soltaniyeh, a shrine so magnificent that it could house the most sacred relics in Shia Islam — and he intended to bring them there.
The sultan meant to transfer the bodies of Imam Ali from Najaf and Imam Husayn from Karbala to his new dome — making Soltaniyeh a centre of Shia pilgrimage to rival the holy cities of Iraq, and the spiritual heart of his empire.
The great dome was raised to be that shrine — a mausoleum fit for the Imams themselves, its scale and splendour a measure not of one king's vanity but of the holiness it was built to hold.
It never happened. The transfer was never realised — historical accounts point above all to the opposition of Shia scholars, who would not see the Imams moved from the shrines where they lay. The bodies stayed in Iraq.
Denied the relics, Oljaitu is said to have had the southern torbat-khaneh chamber built using earth carried from Najaf and Karbala — a fragment of the holy soil, standing in for the shrine that never was.
And so the mausoleum built for the Imams received, in the end, the man who built it. When Oljaitu died in 1316, he was buried beneath his own great dome — the shrine of others become the tomb of its maker.
Without its sultan, Soltaniyeh lost its purpose. The Ilkhanid capital drifted back to Tabriz, the imperial city emptied, and in time almost nothing was left standing on the plain but the dome itself.
The story does not end quietly with Oljaitu's burial. A century after his death, the conqueror Timur (Tamerlane) swept across Iran, and the old Ilkhanid monuments suffered. According to the Castilian envoy Ruy González de Clavijo — who journeyed through this country in the early fifteenth century on his way to Timur's court, and left one of the great travel accounts of the age — Oljaitu's body was exhumed from beneath his dome on the order of Miran Shah, a son of Timur.
It is a bitter coda to a bitter irony. Oljaitu had built the mightiest tomb in Mongol Persia to hold the bodies of saints, and had been refused; he had been buried in it himself instead; and then even that rest was broken, his body dragged from the shrine he had raised. The dome he built to be a place of eternal veneration could not, in the end, keep its own maker in the ground.
But the dome endured. It outlasted Oljaitu, and Miran Shah, and Timur, and the slow centuries of neglect that followed, when the city around it dwindled to a village and the tile fell from its walls. From the 1960s it was painstakingly restored, its structure stabilised, its decoration studied and conserved. And it stands today on the Zanjan plain as it has for seven hundred years — the last and greatest monument of the Mongol kings of Iran, and the tomb of a man who spent his life searching for God and his fortune building God a house.
Soltaniyeh is not an adventure — it is a masterpiece, reached by an easy drive and entered through a door. Its scores reflect that honestly: low on the scale of physical challenge, but very high on Legacy. This is a UNESCO World Heritage monument of the first rank — a structural landmark in the history of world architecture, wrapped in one of the most extraordinary human stories in medieval Iran, and unmatched for the sheer presence of its turquoise dome on the empty plain.
You see it from kilometres away — a single turquoise dome swelling above the flat plain, impossibly large, impossibly alone. There is no city around it now to give it scale or context; just the dome, and the sky, and the grass. And as you come closer and it grows and grows against the horizon, you begin to feel the strangeness of it: that something this vast, this refined, this clearly made to be the centre of a great capital, should be standing here almost by itself, as though the world it belonged to had simply evaporated around it.
Then you step inside, and look up into the shell of the dome forty-eight metres above — the intricate brick, the ghosts of painted plaster, the sheer engineering audacity of a void that size raised seven centuries ago — and the human story rises up to meet the architecture. This was built to be a shrine for the Imams. A Mongol descendant of Genghis Khan, who had been a Christian and a Buddhist and a Sunni before he became a Shia, poured his empire's wealth into a dome meant to draw the whole Shia world to this plain, to make a new Najaf here on the Zanjan steppe. And it did not happen. The saints stayed in Iraq. The dream failed. And the man who dreamed it was laid in the tomb he had built for others — and later even torn back out of it.
That is what stays with you: the feeling of standing inside an ambition — a huge, sincere, doomed ambition, frozen in brick and turquoise. Most great buildings are monuments to success: to a victory, a dynasty, a completed vision. Soltaniyeh is a monument to a reach that exceeded its grasp — to a king who wanted to hold the holiest things on earth and was told no, and who left behind, instead of a pilgrimage city, the most beautiful might-have-been in Iran. You come to see the third-largest brick dome in the world. You leave having stood inside one man's enormous, unfinished dream — and there is nothing else quite like the weight of it.
A turquoise colossus raised by a Mongol khan to house the Imams and make a new Najaf on the steppe — the holiest of shrines that became, when the dream failed, the tomb of the man who dreamed it.
April to June is ideal — the Zanjan plateau is mild and green, the light clean and bright on the turquoise dome, and conditions perfect for exploring both the monument and the surrounding archaeological site. The prime season.
September and October are the other excellent window: settled, comfortable weather and beautiful low light on the brickwork and tile. A fine time to combine Soltaniyeh with the city of Zanjan and the wider north-west.
At over 1,800 m the summer heat is tempered by altitude, and visits are perfectly comfortable, though the midday sun on the open plain can be strong. Mornings and late afternoons are best for both comfort and photography.
Winters on the plateau are cold and often snowy — the dome under snow is a magnificent sight, but chilly for lingering. Come prepared for real cold, and check conditions if travelling in the depths of winter.
The wonder is the dome itself and the story it holds. What follows is the planning detail — logistics, tips, and the questions people ask — tucked away so you can open only what you need.
Soltaniyeh is one of the more accessible sites in this collection — a short, easy trip from the city of Zanjan in Iran's north-west.
In the town of Soltaniyeh, Zanjan Province, north-western Iran, about 40 km south-east of Zanjan and just off the Zanjan–Qazvin road. Zanjan — two to three hours from Tehran, with a train station and airport — is the base. From there it is a short drive; the dome's turquoise cap is visible across the plain long before you arrive.
It is one of the supreme achievements of Persian architecture. At about 48 m it is the third-largest masonry dome in the world (after Florence Cathedral and Hagia Sophia), and the earliest surviving double-shelled dome — an innovation that influenced later Islamic architecture, with scholars linking it even to the Taj Mahal. Built 1302–1312 as the mausoleum of the Mongol sultan Oljaitu, it is a UNESCO World Heritage Site (2005) and the foremost surviving monument of the Ilkhanid dynasty.
Oljaitu (Mohammad Khodabandeh) was the eighth Ilkhanid ruler, a great-great-grandson of Genghis Khan who passed through several religions — Christian in infancy, then shamanism, Buddhism, Sunni Islam and finally, around 1310, Shia Islam. As a devout Shia convert he conceived the dome as a grand shrine to house the relics of the Imams Ali and Husayn, brought from Najaf and Karbala, hoping to make his capital Soltaniyeh a great centre of Shia pilgrimage. When that failed, it became his own tomb.
No. Oljaitu's plan to bring the remains of Imam Ali and Imam Husayn to Soltaniyeh was never realised — historical accounts attribute the failure above all to the opposition of Shia scholars, who resisted moving the Imams from their shrines in Iraq. Having built a mausoleum fit for the Imams, Oljaitu was himself buried in it when he died in 1316. The southern torbat-khaneh chamber is said to have been built using earth from Najaf and Karbala.
He was buried beneath his dome in 1316, and the city declined as the capital returned to Tabriz. Later, in the Timurid period, his tomb was violated: according to the Castilian envoy Ruy González de Clavijo, who passed through in the early 15th century, Oljaitu's body was exhumed on the order of Miran Shah, a son of Timur. The dome itself survived, and was extensively restored from the 1960s onward.
Allow an hour or two for the dome — the vast interior, the brick and plaster decoration, the muqarnas, and the upper gallery with close views of the structure. The surrounding Ilkhanid archaeological site, the nearby Chelebi Oghlu shrine, and the city of Zanjan (bazaar, laundry-house museum) can fill more time. It pairs naturally with the wider north-west.
Spring (April–June) and autumn (September–October) are ideal — mild weather on the Zanjan plateau and clear light on the turquoise dome. At over 1,800 m, winters are cold and snowy (atmospheric but chilly), and summers warm but pleasant at altitude. The shoulder seasons give the most comfortable conditions and the best photographs.
Soltaniyeh is the crowning monument of Ilkhanid Iran — the age when the Mongol conquerors, having shattered the old order, remade themselves as patrons of Persian art and became, in Oljaitu, Shia kings. It stands in a corner of the country rich in such layered history. Westward lies Takht-e Soleyman, the Sasanian sacred-fire sanctuary by its bottomless lake, which the Ilkhanids themselves treasured and rebuilt as a summer palace — Zoroastrian holiness and Mongol power in one place, a natural companion to Oljaitu's dome. The whole north-west, around the base city of Zanjan, is a country of bazaars, caravanserais and mountain roads. Come for the dome; discover the strange, brilliant world of the Mongol kings who became Persian.
The sacred fire of kings by a bottomless volcanic lake — the great Zoroastrian sanctuary of Azargoshnasp, which the Ilkhanids prized so highly they built a summer palace amid its ruins. Mongol and Sasanian history entwined. Read the article →
The handsome base city for a Soltaniyeh visit — with one of Iran's finest covered bazaars and the remarkable Rakhtshooykhaneh, a historic public laundry-house now a folk museum. The gateway to the Ilkhanid north-west.
Around the dome lie the remains of Oljaitu's imperial capital — citadel walls, the Chelebi Oghlu shrine, and the ghost of a planned Mongol city that once rivalled the great capitals of the age before it vanished into the plain.
The engineering marvel itself: the world's earliest surviving double-shelled dome, an inner and outer skin that made this vast turquoise vault possible — and set a template that Persian and Mughal builders would follow for centuries.
Come in spring or autumn, from Zanjan, and give the dome an afternoon. See it first from the road, growing out of the plain — then stand beneath it, look up into the great turquoise shell forty-eight metres overhead, and hold the story in your mind: that a Mongol khan who had worn five faiths built this to be the shrine of the Imams, to make a new Najaf on the Zanjan steppe, and was refused; that he was buried here in the tomb he had raised for others, and later torn back out of it; and that of the whole imperial city he dreamed, this alone remains, turquoise and vast and half-empty of its meaning, on the empty plain. It is the most beautiful unfinished ambition in Iran — and it has been waiting seven hundred years for you to come and feel its weight.
Untamed Iran prefers official, scholarly and first-hand sources, and is careful to separate what is established from what is tradition. Soltaniyeh is exceptionally well documented — a UNESCO monument with a rich historical record reaching back to contemporaries of Oljaitu himself; the human story is drawn from those sources, with the more legendary details flagged. The following are the sources this page draws on:
Facts last reviewed July 2026. Established: the Dome of Soltaniyeh as the mausoleum of the Ilkhanid sultan Oljaitu (Mohammad Khodabandeh), built 1302–1312 at the Ilkhanid capital of Soltaniyeh (Zanjan Province); its ~48 m height, octagonal plan, turquoise faience and status as the earliest surviving double-shelled dome and the third-largest masonry dome in the world after Florence Cathedral and Hagia Sophia; its UNESCO World Heritage inscription (2005); Oljaitu's succession of religious affiliations culminating in Twelver Shiism (c. 1310) and his role as the first ruler to make Shiism official in Iran; the intention to house the relics of the Imams Ali and Husayn and make Soltaniyeh a pilgrimage centre; the failure of that plan; and Oljaitu's death (1316) and burial in the dome. Reported by a contemporary source: the later exhumation of Oljaitu's body on the order of Miran Shah, son of Timur, recorded by the Castilian envoy Ruy González de Clavijo. Tradition / attributed: the precise reasons the relic-transfer failed (accounts point chiefly to the opposition of Shia scholars) and the use of earth from Najaf and Karbala in the torbat-khaneh, given as historical report rather than documented certainty; the influence on the Taj Mahal is a scholarly view. Approximate: the coordinates and distances, which vary slightly between sources.