Analysis of gold bar published a few months before 500th anniversary of battle that forced Cortés to beat a temporary retreat

This article is more than 8 months old

This article is more than 8 months old

A new scientific analysis of a large gold bar found decades ago in downtown Mexico City has confirmed it was part of the plunder Spanish conquistadors abandoned as they beat a temporary retreat from the Aztec capital.

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Mexico’s National Institute of Anthropology and History (Inah) announced the findings of new tests of the bar in a statement on Thursday, a few months before the 500th anniversary of the battle that forced Hernán Cortés and his soldiers to temporarily flee the city on 30 June 1520.

A day earlier, the Aztec emperor Moctezuma was assassinated, prompting a frenzied battle that forced Cortés, his fellow Spaniards and their indigenous allies to flee for their lives.

A year later, Cortés would return and lay siege to the city, which was already weakened with supply lines cut and diseases that accompanied the Spanish invaders taking a toll.

The bar was originally discovered in 1981 during a construction project some 16ft (5m) underground in downtown Mexico City – which was built on the ruins of the Aztec capital Tenochtitlán – where a canal that would have been used by the fleeing Spaniards was once located.

The bar weighs about 2kg (4.4lb) and is 26.2cm (10.3in) long, 5.4cm wide and 1.4cm thick.

Facebook Twitter Pinterest The bar was originally discovered in 1981 beneath the Mexico City streets, where a canal that would have been used by the fleeing Spaniards was once located. Photograph: National Institute Of Anthropolo/Reuters

A fluorescent X-ray chemical analysis was able to pinpoint its creation to 1519-20, according to Inah, which coincides with the time Cortés ordered gold objects stolen from an Aztec treasury to be melted down into bars for easier transport to Europe.

Historical accounts describe Cortés and his men as heavily weighed down by the gold they hoped to take with them as they fled the imperial capital during what is known today as the Sad Night, or Noche Triste, in Spanish.

“The gold bar is a unique historical testimony to a transcendent moment in world history,” said archaeologist Leonardo López Luján, who leads excavations at a nearby dig where the Aztecs’ holiest shrine once stood.

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Until the recent tests, scholars of the last gasps of the Aztec empire only had historical documents to rely on as confirmed sources, added López Luján.

A more in-depth and technical description of the tests performed on the bar is published in the January issue of the magazine Arqueología Mexicana.