Mostar’s Old Bridge: Construction and Crossing

Mostar’s Old Bridge spans the Neretva River in present-day Bosnia and Herzegovina. An assessment by the International Council on Monuments and Sites places it on a trade route between the Adriatic and the mineral-producing regions of central Bosnia. Soldiers, merchants, and other travelers needed to cross the river. The settlement gradually spread across both banks, and the bridge connected their markets.

The sixteenth-century stone bridge was not the first crossing at this site. Earlier timber remains were discovered during reconstruction. Combining stratigraphy, radiocarbon dating, and dendrochronology, Obelić and colleagues identified a wooden suspension bridge and a later rigid-frame timber bridge. The dates of the wood cannot be treated directly as the opening dates of entire bridges, but they establish that the crossings and bridgehead defenses were not built in a single operation. The stone bridge continued a long-used route.

References: [1] [2]

Research traces the stone-bridge project to an order issued by Sultan Suleiman I in 1557 and generally dates its completion to 1566. The bridge inscriptions and early travelers’ accounts used as evidence refer to the Islamic year 974; the inscribed date and later Gregorian accounts still require comparison. The cited studies do not establish an additional, precise opening date.

Engineering papers associate the bridge’s design and construction with Hayreddin, described as a pupil of the Ottoman architect Sinan. Other studies attribute the overall design to Sinan and completion to Hayreddin. What can be established is that the bridge belonged to the engineering practice of this architectural tradition; the master’s and pupil’s names are not interchangeable. Surviving evidence also cannot reconstruct the daily sequence of work. The passage of several years between the project’s inception and completion does not prove that construction continued uninterrupted for that entire period.

References: [2] [3] [4]

The Old Bridge used a single stone arch. Prewar surveys and reconstruction studies give slightly different clear spans on the north and south sides, about 28.6–28.7 meters, with a rise of approximately 12 meters and a load-bearing arch thickness of about 0.8 meters. The deck climbed toward the center, creating a steep crossing for pedestrians. This form incorporated the rock on both banks and the abutments into the structure as a whole; the bridge cannot be understood merely as a thin ribbon of stone suspended above the water.

The arch stones were chiefly made of a local oolitic limestone called tenelija, assembled with very thin mortar joints and connected by iron dowels and cramps. The metalwork fitted into holes and grooves cut beforehand in the stones and was secured with poured lead. Harder limestone was used for the paving and covering slabs. Stone, mortar joints, and metal connections worked together: a stone bridge did not mean blocks simply stacked without connections.

References: [3]

Maja Popovac’s reconstruction paper explains that stone stiffening ribs and spandrel walls stood above the main arch, while two weight-reducing cavities avoided a heavy, solid mass above its crown. Transverse raised strips on the deck helped pedestrians avoid slipping on the slopes. The components were not all identical in shape, so stonecutting, placement, and control of the joints required coordination on site.

Records of the original construction are insufficient. Timber centering and possible work during the low-water season are explanations researchers infer from the structure. The story that Hayreddin fled for fear of collapse is explicitly identified in the paper as a legend. Rather than treating these accounts as eyewitness records, more reliable evidence comes from surviving connection holes, worked surfaces, and prewar surveys, which reveal the precise assembly techniques actually employed.

References: [4]

The Old Bridge underwent many maintenance campaigns. During Austro-Hungarian rule, the approaches and paving levels at both ends were altered to improve passage. Further repairs in the mid-twentieth century addressed water infiltration, voids, and structural damage. On 9 November 1993 the original stone arch was destroyed by wartime shelling. The arch spanning the river today belongs to the subsequent reconstruction and should not be presented without distinction as the sixteenth-century original.

Reconstruction required more than photographs of the exterior. Engineers combined a 1955 survey, photogrammetry from 1982, and investigation of the surviving remains to recover the geometry. They also examined the abutment rock, voids, and cracks in old stones. Only a limited number of blocks were recovered from the water, and some apparently intact stones could have internal damage. It would therefore be inaccurate simply to claim that all the original stones were returned unchanged to their former places.

References: [2] [3] [4]

Reconstruction was jointly advanced by the City of Mostar, the United Nations Educational, Scientific and Cultural Organization, the World Bank, and technical specialists from several countries. Facing winter and spring fluctuations in river level, the builders supported the masonry on a main steel framework with timber decking above it, marking, measuring, and installing stones individually. These modern construction safeguards served the recovery of the historical form; they did not completely reenact the sixteenth-century building site.

The reconstructed bridge was inaugurated on 23 July 2004. The heritage assessment of 2005 noted that the new bridge predominantly used new materials and that continuity of original fabric had been lost. It also recognized that reconstruction rested on extensive investigation and that the form, material types, techniques, and relationship to the urban landscape remained recognizable. What was restored was both a pedestrian crossing and a shared landmark for the two banks, but commemorative significance cannot replace an account of old and new components and successive historical layers.

References: [1] [2] [4]