Tumbaga Metal: The discovery of the first sunken treasure in Spain

Decades after Christopher Columbus’ first voyage to the New World in 1492-1493, Spanish conquistadors discovered vast amounts of gold, silver, and copper. This discovery increased Spain’s influence in the world economy. Large quantities of these three metals were not only important to Spain since its colonies, but the nation became the center of an empire that traded with the rest of the world, importing and exporting goods between other nations.

Before the mid-16th century, colonial mints producing gold and silver coins had not yet been built in Mexico or Peru. Hernando Cortés, Spain’s main conquistador in Mexico, shipped to Spain the few precious metals that could be looted and melted down for Aztec and Tarascan jewelry, idols, and other artifacts. These items were melted down into raw bars of gold, silver, and copper. But there was a problem: the bars never reached Spain.

In the summer of 1992, a treasure salvage boat off the west coast of Grand Bahama Island detected an unbelievably large amount of metal buried in the ocean. When the family working for Marex donned their scuba gear to investigate, they discovered several bars of silver and gold, but that discovery was just the tip of the iceberg. After contacting the Marex headquarters, more than two hundred crude rods were brought to the surface from the same site.

After investigating the gold and silver ingots, poured with some copper, archaeologists discovered that they came from a Spanish ship that sank in 1528, as a result of a hurricane or the ship ran aground in shallow water. Most of the bars could be identified from the marks that had been stamped after they had been cast as completely as possible, but as quickly as possible, using crude moulds, some of which were simply depressions in the sand.

These bars called “tumbaga” were identified by four details engraved on each one:

1. The letters BV with “~” above the B and “o” above the V, possibly signifying Bernardino Vásquez, one of Cortés’ fellow conquistadors, who supervised the mixing and molding of each bar.

2. The purity of each bar was marked in Roman numerals as a percentage of 2400 for 100% pure; 1200 for 50%, 600 for 25% and so on.

3. Serial numbers, beginning with the letter R followed by Roman numerals.

4. Fiscal stamp, part of a circular stamp whose legend (joint) reads CAROLVS QVINTVS IMPERATOR of Charles V, King of Spain and Holy Roman Emperor. The seal probably indicates the “King’s Fifth”: 20 percent of the treasure goes to the King.

The discovery of this collection of bars is of great historical significance to the vast and exciting stories of shipwrecked “Spanish treasures”, such as chests full of gold doubloons from the early Spanish colonial empire. Furthermore, it is the oldest treasure to be discovered in the Atlantic Ocean since the Spanish coastal empire between 1492 and 1820. The conquistadors subdued mainly the native population and did not impose regular mining before 1528.

The word “tumbaga” originates from a historical document of a Spanish governor in the Philippine islands from the early 18th century, who used the term “Tumbaga metal” to refer to a gold and copper alloy used among the natives. The term today also includes an alloy of silver and copper, which comprised most of the bars. (See attached link for The “Tumbaga Saga”).