S10-16

A Preliminary Study on the Use of Copper Alloy Materials in the 13th Century CE: The Case of Bronze Rings Recovered From the Investigator Shoal Shipwreck, Palawan, Philippines

Nero M. Austero, Bobby Orillaneda, Emil Nell Bersamira

National Museum of the Philippines, Philippines

This paper presents the results of the preliminary study of the bronze rings recovered from the Investigator Shoal shipwreck. The site was discovered by a Filipino fisherman, who recovered about 200 pieces of high-fired Chinese ceramics in 1989. Along with several 13th century Common Era (CE) Chinese qingbai and stoneware ceramics, 54 kilograms or approximately 3000 pieces of bronze rings were recovered from the site during a series of archaeological excavations in 1990, and 1991. Some rings were discovered inside stoneware jars packed by ten pieces, while others were bundled with rattan ties and arranged separately in layers by woven mats. Each ring resembled an armband or bracelet, thereby suggesting that these rings may have been traded or smuggled for ornamental purposes. Interestingly, other copper alloy materials such as spiral rings and armbands or bracelets were also found in several terrestrial sites, as well as from other shipwreck sites in the country. However, the bronze rings from the Investigator Shoal were all plain, cast, and undecorated, therefore, these rings could have been used otherwise to adorn weapons, and/or ritual vessels, instead of being used as jewellery pieces. The rings measure approximately 10 cm in diameter with a wire diameter (cross-section) ranging from 0.6 cm to 0.9 cm. In addition, portable X-Ray Fluorescence (pXRF) analysis revealed the rings were composed of a leaded-bronze mix, consisting of 48.89%-48.97% copper (Cu), 23.58%-23.92 % tin (Sn), 4.62%-9.98 % iron (Fe), 8.78 %-19.72% lead (Pb), and 3.02%-5.92% antimony (Sb), with trace amounts of zinc (Zn) and nickel (Ni). The Investigator Shoal’s bronze rings, indeed, are of outstanding importance as they shed light on the use and manufacture of copper alloys during the 13th century CE. Besides, its discovery at the periphery of the West Philippine Sea, may further illustrate the vibrant commercial exchange between China and the Philippines during that period.