This Aztec Gold Bar Was Dropped by Spanish Conquistadors During Famous Escape From Tenochtitlan, Scientists Say

In 1981, a worker in Mexico City found a gold bar just north of Alameda Central—the oldest public park in the Americas—during the construction of a bank. Now, researchers say the bar was part of the stolen treasure looted from the Aztec capital by Hernán Cortés and his Spanish conquistadors five centuries ago.

A team from Mexico's National Institute of Anthropology and History (INAH) analyzed the roughly 4 pound bar using X-rays, coming to the conclusion that it was lost during the so-called "La Noche Triste" or "Sad Night"—a significant event of the Spanish conquest.

La Noche Triste refers to the night of June 30, 1520, when the Aztecs drove Cortés, his invading army and their native allies out of their capital Tenochtitlan—which was eventually renamed as Mexico City.

The bar is a "key piece" in the puzzle of this historical event, said Leonardo López Luján, director of the Templo Mayor Project (PTM)—an INAH archaeological initiative which is excavating Tenochtitlan's main temple complex.

During the Spanish retreat, the bar of gold was dropped into one of the canals that ran through Tenochtitlan and into the surrounding Lake Texcoco—which has now drained away.

According to Luján, the location that the gold bar was found in corresponds to that of the Aztec Toltecaacaloco Canal, which Cortés and his men used to make their escape. Its characteristics closely match those of gold bars which are referred to in historical sources describing the event.

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But despite these pieces of information, Luján noted that it was necessary to conduct X-ray analysis of the gold bar in order to authenticate it. To do this, scientists at The National Autonomous University of Mexico (UNAM) used a portable piece of equipment known as "Sandra"—which is highly sensitive and non-destructive.

gold bar
Image of the gold bar. MNA-INAH

This analysis revealed that the bar consisted of around 76.2 percent gold, 20.8 percent silver and roughly 3 percent copper. This composition is similar to others recovered by PTM.

"The so-called 'Noche Triste' is among the episodes of the conquest that will be remembered this year, and there is only one piece of material evidence from it: a gold bar that sank 500 years ago in the canals of Tenochtitlan, and which recent analysis confirms came from the [Spaniards'] flight," an INAH statement read.

Cortés and the Spaniards were initially welcomed by the Aztec emperor Moctezuma when they first arrived at Tenochtitlan toward the end of 1519, AFP reported. However, the relationship between the two groups soon soured and the Spanish took the emperor hostage.

Then in June 1520, Cortés learned that Governor Velázquez of Cuba had sent a large group of men to arrest him for insubordination—his mission to Mexico had not been officially sanctioned.

Cortés headed to the coast to fend off the expedition leaving his trusted lieutenant Pedro de Alvarado in charge. While he was successful in repelling Velázquez's mission, the situation in Tenochtitlan had taken a turn for the worse.

De Alvarado had received information that the Aztecs were planning an attack on him. In response, he ordered the slaughter of several Aztec nobles and priests who were taking part in celebrations at Tenochtitlan's main temple.

As a result, the Aztecs revolted and laid siege to the compound where the Spanish were staying and holding Moctezuma captive. Once Cortés had returned to the city in late June, he realized the precariousness of the situation and took the decision to try and leave the city by night on June 30, taking as much looted treasure as they could carry.

This Aztec Gold Bar Was Dropped by Spanish Conquistadors During Famous Escape From Tenochtitlan, Scientists Say | Tech & Science