In Arizona, researchers have reportedly discovered the oldest firearm ever excavated on the mainland of the United States.

This bronze cannon, also known as a wall gun, is linked to the initial European expedition to the Southwest. It was found on the floor of a Spanish structure made from stone and adobe in southern Arizona, near the Santa Cruz River, in 2020, as revealed in a new study published in the International Journal of Historical Archaeology.

Through modern carbon dating techniques, the study’s authors, Deni J. Seymour and William P. Mapoles, determined that this weapon had been lying in ruins within the building for 480 years, which was part of San Geronimo III, the first European settlement in the Southwest established in 1540.

Excavation work commenced in late 2021 “to better understand the context of the gun and uncover further evidence of the Spanish settlement,” the study’s authors noted.

The gun’s design aligns with that of the mid-to-late 1400s, and it had become practically outdated by the time of the expedition, as noted by Seymour and Mapoles.

It seems the cannon was never used as it was left behind during an attack by the indigenous Sobaipuri O’odham people on San Geronimo III, which, the researchers argue, resulted in the Spanish retreating from southern Arizona for 150 years.

“This gun is an invaluable artifact, and it is undoubtedly the earliest known surviving firearm in the United States and possibly one of the oldest securely situated in the New World,” the researchers stated.

A Failed Spanish Expedition

The conquistador Francisco Vásquez de Coronado, then governor of the New Galicia province of New Spain (modern-day Mexico), embarked on a quest across the southwestern U.S. seeking treasures and routes to Asia.

Coronado, at the age of 27, commanded a contingent of 240 mounted soldiers, 60 infantry soldiers, and 800 Native Americans and enslaved individuals in their expedition starting in 1540, as reported by the Oklahoma Historical Society.

The mission was deemed unsuccessful since no gold or silver was discovered, and the native tribes encountered were too few to establish settlements for exploitation as the Spanish intended, according to the study.

During the period when the expedition was abandoned, San Geronimo III was attacked by the Sobaipuri O’odham people. The settlement was devastated, and its residents either died or fled to Mexico.

Researchers suspect that the site they explored in 2020 near the Santa Cruz River represents San Geronimo III. They uncovered a “remarkably rich collection,” featuring the bronze cannon along with thousands of artifacts such as arrowheads, lead bullets, and weapon components that provided substantial evidence of the conflict that drove the Spanish out of the area for a century and a half.

“Europeans did not return to what eventually became southern Arizona for another 150 years, marking it as the earliest and most significant Native American rebellion in the continental U.S.,” the study’s authors remarked. “This revelation is surprising considering that prior to this discovery, the O’odham were thought to have only played a minor role during the early conquest episodes.”

Cannon Abandoned Following Native Attack on Spanish Settlement

The wall gun was crafted to be mounted on a wooden tripod along fortification walls, a design that became popular in the 1400s. It was adaptable, easily transportable, and effective for both offense and defense, according to researchers.

The weapon was ideally suited for the expedition due to its “lightweight” design, “durable nature, and ease of operation,” the study’s authors explained, adding, “A pair of these could easily be secured on a horse or mule, with one or more on each side to maintain balance during transportation.”

This cast-iron firearm was capable of handling heavy loads of buckshot or round lead projectiles. To fire a single lead ball, gunpowder would first be poured into the muzzle, followed by the round ball and a wad of paper or grass to prevent the ball from rolling out when the muzzle was tilted downward, as detailed by the researchers.

Regarding these shotguns, it should be noted that this particular firearm has not been discharged. The absence of black markings within the barrel, a typical sign of wear, supports this claim.

Researchers suggest that the reason for the weapon not being loaded or fired is due to the rapid onset of the Sobaipuri O’odham attack, which occurred very early in the morning, catching the Spanish forces off guard; many were slain while still in their beds. According to Seymour and Mapoles, the gunners were either “killed, captured, or fled.” They also emphasized that such an expensive weapon would usually not be abandoned under normal conditions.

Now, nearly 480 years later, this important historical firearm has been unearthed, along with another cannon that is set to undergo examination soon.

“This location is remarkable and may shed light on why one cannon was left here, in addition to a second one recently found that will be explored in a subsequent article,” stated the researchers.