A new chemical analysis of a large gold bar found under a Mexico City street in 1981 has shed light on its centuries-old origins. As Mexico’s National Institute of Anthropology and History (INAH) announced last week, the precious metal was probably dropped in a canal by Spanish invaders as they retreated from the Aztec capital of Tenochtitlán on June 30, 1520, the Noche Triste, or “Night of Sadness.”
Construction workers discovered the 4.4-pound gold bar at a depth of some 16 feet belowground. X-ray fluorescence analysis detailed in the January issue of Arqueología Mexicana revealed the chemical composition of the bar, providing data experts could then align with other gold samples from known years, explains José Luis Ruvalcaba of the National Autonomous University of Mexico in a statement. In this case, the composition of the gold bar was similar to those recovered at nearby Templo Mayor, the central temple of Tenochtitlán.
“The golden bar is a unique historical testimony to a transcendent moment in world history,” archaeologist Leonardo Lopez Lujan, who is leading excavations at Templo Mayor, tells Reuters’ David Alire.
The Noche Triste marked the end of conquistador Hernán Cortés’ first attempt to conquer Tenochtitlán. Ignoring orders from his superiors, Cortés sailed from Cuba to the North American mainland with 500 soldiers, 100 sailors and 16 horses. Upon landing in March 1519, he learned how the local people resented the Aztecs, who had steadily gained control of the region through wars of expansion. Under Emperor Moctezuma II, or Montezuma, the military powerhouse required monetary and human tributes from conquered territories.
Cortés formed alliances with the cultures conquered by the Aztecs and marched on Tenochtitlán. Although Moctezuma tried to bribe Cortés and his army to leave, the conquistador was soon allowed to enter the city unopposed—possibly due to the Aztecs’ belief in the return of the white, bearded god Quetzalcóatl, or as a trap. Cortés then took Moctezuma prisoner and ordered his treasures melted into gold bars for easier transport.
When Cortés left the city to face a Spanish army sent to remove him from command, the people of Tenochtitlán took advantage of his absence and rebelled. When Cortés returned, he was forced to escape by night.
Spanish accounts of the Noche Triste say the Aztec people lost respect for their captured emperor, whom they killed with stones and arrows when he tried to give a speech. Aztec accounts, on the other hand, suggest the Spaniards either assassinated him or killed him in battle.
As Cortés’ soldiers fought their way out of the city, they suffered heavy losses. Those that survived tried to escape with as much treasure as they could carry; one vessel of soldiers and valuables subsequently sank in Lake Texcoco.
“It is incalculable how much our people suffered,” Cortés later wrote, per a translation. “As well Spaniards as our Indian allies of Tascaltecal, nearly all of whom perished, together with many native Spaniards and horses, besides the loss of all the gold, jewels, cotton cloth, and many other things we had brought away.”