- Also called:
- Allahverdi Khan Bridge and Pol-e Si-o-Se Chashma
Si-o-Se Pol
What is Si-o-Se Pol, and where is it located?
When was Si-o-Se Pol constructed, and by whom?
What is the significance of the name Si-o-Se Pol?
Si-o-Se Pol, double-deck, brick-and-stone masonry arch bridge built in the early 17th century during Safavid rule in the city of Isfahan, Iran. The bridge, whose name means “The Bridge of 33 Arches” in Farsi, spans the Zayandeh River, connecting uptown and downtown Chahār Bāgh (“Four Gardens”; historical avenue between north and south Isfahan). It is Isfahan’s longest bridge, notable for its architectural craftsmanship and continual use as a public gathering space since its construction.
History
Political background
In 1598 Shah ʿAbbās I (Safavid ruler of Persia from 1588 to 1629) moved the capital of his kingdom from Qazvin to Isfahan. A key reason for this shift was to remove his administrative center from politically tense areas. The Safavids had been in conflict with the Sunni forces on two frontiers, with Ottoman aggression to the west and Uzbek opposition to the east, ever since Ismāʿīl I, great-grandfather of ʿAbbās I, made Shiʿism Persia’s state religion in the 16th century.
The Shiʿi sect of Islam believes that Prophet Muhammad’s cousin, ʿAlī ibn Abī Ṭālib, was the prophet’s rightful successor as the leader of the Islamic world; the Sunnis believe that a leader should have been chosen from among the masses, leading to tensions between these two major Islamic sects.
The Zayandeh River, a crucial source of water close to Isfahan, was another important factor in the shah’s choice. As the shah expanded Isfahan to make it suitable as a capital, the river was brought within the city walls and divided the city into two. As the Zayandeh is unnavigable by boat, the construction of bridges was essential for the transport of goods and people across the newly expanded metropolis.
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Construction history
The construction of the Si-o-Se Pol began in 1599. Allahverdi Khan, one of Shah ʿAbbās’s key generals, oversaw the construction as its patron. The architect commissioned by Khan to design the bridge is not named in historical sources, though tradition identifies the architect as either Hossein Banā Isfahani or Mir Jamāl al-Dīn Muhammad Jābirī. Khan could afford a project of this scale thanks to his prominence as a general and his additional appointment as governor of Fārs province.
The structure, called Allahverdi Khan Bridge, was completed in 1602, and its 33 principal arches became the source of its popular name (si-o-se is the word for “33,” and pol means “bridge” in Farsi). Like many of Isfahan’s bridges, Si-o-Se Pol also functions as a dam, helping to control water flow in the area. The archways are furnished with sluice gates that can open to allow excess water to pass through in periods of flooding.
After the shah finished transforming Isfahan into the capital, the Chahār Bāgh, Isfahan’s central commercial artery, expanded across the river via Si-o-Se Pol. The bridge thereby connected Chahār Bāgh avenue to the New Julfa neighborhood, an economically important district housing emigrant artisans from Armenia.
The bridge’s engineering feats, monumental scale, and architectural beauty earned it international fame. According to reports by European travelers, the interior of the structure displayed erotic artworks prior to the 19th century.
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Specifications
The Si-o-Se Pol measures about 970 feet (296 meters) in length and 46 feet (14 meters) in width. The stones in its foundation were laid with sarooj, a traditional mortar (material used to bind bricks and stones during construction). The upper section of the bridge, comprising the upper story, the deck, and a row of smaller arches, is crafted from adobe brick (a sun-dried brick made from dense clay) and plaster mortar, whereas the lower part is constructed in stone.
Traditional bridge construction in Iran, Oman, and Afghanistan often involved the use of sarooj, a special hydraulic mortar (a mortar that hardens on contact with water) made of lime, clay, sand, and, in some recipes, gypsum. Sarooj’s hydraulic properties made it especially suitable for bridge foundations.
The wide arches that lend their name to the structure are arranged between the bridge’s piers, with two rows of smaller arches along the top story around the deck. The upper arches are smaller and arranged in groups of three, such that one small upper arch corresponds to a pier, followed by two arches corresponding to a large lower arch in a repeating pattern. The widest of the lower arches spans about 18 feet (5.5 meters).
A major reconstruction project in 1970 increased the bridge’s load capacity by adding a concrete deck slab to the walkable portion of the bridge, distributing weight to the bridge’s piers and enabling it to support vehicles.
Usage and role in social life
Si-o-Se Pol’s central lane was intended for livestock traffic, and the side lanes were built to accommodate pedestrians. Si-o-Se Pol also served as a cultural hot spot because of its proximity to Chahār Bāgh avenue. The Chahār Bāgh ran alongside a series of opulent buildings that housed members of the Safavid court, and social activities on both sides of this square spilled over to the bridge. Coffeehouses lined the avenue, and Si-o-Se Pol provided seating for royal spectators at boat races and other events hosted on the river. Following a 1609 decree by ʿAbbās I, the bridge and the surrounding coffeehouses were open solely to women on Wednesdays. Public spaces otherwise occupied by men thereby became the exclusive preserve of women once a week, and on these days only women were permitted to sell wares on the bridge and along the avenue.
Si-o-Se Pol in modern Iran
Si-o-Se Pol remains a center of Isfahan social life in modern times. The bridge is the site of many gatherings of locals and tourists, and activities around the bridge include kite flying and picnicking. Each side of the bridge contains a covered arcade, and the trademark arches dotting the promenades double as shaded seating areas for resting, socializing, and hosting outdoor events.
Protests have also been held near the bridge in recent years, as the depletion of the Zayandeh River has led to criticism against the Iranian government’s water distribution practices. Government officials have redirected the river’s water from Isfahan to Yazd and other neighboring provinces for agricultural and industrial use, leaving the riverbed surrounding Si-o-Se Pol dry for most of the year, apart from periods when dams are opened to irrigate wheat fields east of Isfahan. Tens of thousands attended a protest in the dried riverbed in front of Si-o-Se Pol in November 2021 to challenge these policies. Experts have warned that this paucity of water, already a significant problem in Iran’s typically arid environment, will be exacerbated by climate change.