An act of faith, an act of theft
On February 5, 1484, King Dhammazedi of the Hanthawaddy Kingdom commissioned the casting of a monumental bronze bell for the Shwedagon Pagoda in Dagon, now Yangon. Contemporary accounts state it was cast from 180,000 viss (a traditional Burmese unit of mass), equivalent to about 294 metric tons. The alloy contained copper and tin, with silver and gold added for symbolic value and to increase its resonance. Standing around 6 meters tall, it was believed to be the largest bell ever successfully cast. An Italian gem merchant, Gasparo Balbi, visited the pagoda in 1583 and described a massive bell covered from top to bottom in a script that no one could decipher.
In 1608, the Portuguese mercenary and self-declared king of Syriam, Filipe de Brito e Nicote, plundered the pagoda. His prize was the great bell, which he intended to melt down to forge cannons. De Brito's men rolled the bell down a hill to a waiting raft on Pazundaung Creek and used elephants to haul it to the Bago River. The raft, lashed to de Brito's flagship, could not support the immense weight. At the confluence of the Bago and Yangon rivers, the raft disintegrated, and the bell plunged to the riverbed, reportedly taking the ship with it.
The science of a 400-year search
The search for the Dhammazedi Bell is a difficult problem in underwater archaeology, compounded by a difficult environment. The confluence of the Bago and Yangon rivers is a dynamic estuarine zone with near-zero visibility, strong tidal currents, and a thick shifting riverbed of mud and silt. Over four centuries, the bell has likely been buried under as much as 7.6 meters (25 feet) of sediment.
Modern search efforts use a suite of remote sensing technologies to probe the riverbed without intrusive digging. Teams have deployed side-scan sonar, which uses acoustic pulses to create detailed topographical maps of the river floor. Magnetometers are towed behind survey vessels to detect magnetic anomalies, which could indicate a large metal object. But bronze is not strongly magnetic, making the bell a difficult target for this method. Sub-bottom profilers use low-frequency sound waves to penetrate the sediment layers, showing what lies buried beneath the mud.
Despite numerous surveys, including one in 2010 by Australian filmmaker Damien Lay that identified 14 shipwrecks and two promising targets, the bell is still missing. Sonar images have revealed large, bell-shaped objects, but these could be shipwrecks or natural rock formations. The river's ever-changing course over the centuries further complicates the search; some historians suggest that the confluence's location in 1608 may be different from its position today. Definitive identification will require visual confirmation or direct physical contact, a hazardous task in the murky, fast-flowing water.