Mesoamerican copper smelting technology aided colonial weaponry

When Spanish invaders arrived in the Americas, they were being usually in a position to subjugate the local peoples thanks, in part, to their exceptional weaponry and technological know-how. But archeological evidence indicates that, in at least 1 critical respect, the Spaniards were being fairly dependent on an more mature indigenous technological know-how in components of Mesoamerica (present day Mexico, Guatemala, Belize, and Honduras).

The invaders required copper for their artillery, as perfectly as for coins, kettles, and pans, but they lacked the awareness and abilities to create the steel. Even Spain at that time experienced not developed the steel domestically for hundreds of years, relying on imports from central Europe. In Mesoamerica they experienced to depend on local smelters, furnace builders, and miners to create the critical material. These experienced workers, in flip, were being in a position to cut price for exemption from the taxes levied on the other indigenous men and women.

This dependence ongoing for at least a century, and most likely as lengthy as two hundreds of years or much more, in accordance to new findings revealed in the journal Latin American Antiquity, in a paper by Dorothy Hosler, professor of archeology and ancient technological know-how at MIT, and Johan Garcia Zaidua, a researcher at the College of Porto, in Portugal.

The research, at the web-site of El Manchón, in Mexico, designed use of information gleaned from much more than 4 hundreds of years worth of archeological capabilities and artifacts excavated by Hosler and her crew around a number of many years of fieldwork, as perfectly as from lab operate and historical archives in Portugal, Spain, and Mexico analyzed by Garcia.

El Manchón, a large and distant settlement, in the beginning displayed no evidence of Spanish existence. The web-site consisted of a few steep sectors, two of which displayed lengthy residence foundations, some with inside rooms and spiritual sanctuaries, patios, and a configuration that was conceptually Mesoamerican but unrelated to any known ethnic teams these as the Aztec. In between the two was an region that contained mounds of slag (the nonmetallic material that separates out all through smelting from the pure steel, which floats to the area).

The Spanish invaders urgently required great quantities of copper and tin to make the bronze for their cannons and other armaments, Hosler claims, and this is documented in the historical and archival data. But “they didn’t know how to smelt,” she claims, whilst archaeological facts advise the indigenous men and women experienced previously been smelting copper at this settlement for numerous hundred many years, generally to make ritual or ceremonial products these as bells and amulets. These artisans were being highly experienced, and in Guerrero and in other places experienced been producing elaborate alloys together with copper-silver, copper-arsenic, and copper-tin for hundreds of many years, working on a modest scale making use of blowpipes and crucibles to smelt the copper and other ores.

But the Spanish desperately needed large quantities of copper and tin, and in session with indigenous smelters launched some European technological know-how into the course of action. Hosler and her colleagues excavated an enigmatic feature that consisted of two parallel programs of stones major towards a large cake of slag in the smelting region. They identified this as the stays of a consequently-significantly-undocumented hybrid style of closed furnace design and style, powered by a modified hand-held European bellows. A modest regional museum in highland Guerrero illustrates just these a hybrid furnace design and style, together with the modified European-launched bellows technique, capable of producing large volumes of copper. But no precise stays of these furnaces experienced formerly been found.

The period when this web-site was occupied spanned from about 1240 to 1680, Hosler claims, and might have extended to the two before and later times.

The Guerrero web-site, which Hosler excavated around 4 discipline seasons ahead of operate experienced to be suspended for the reason that of local drug cartel exercise, has large heaps of copper slag, developed up around hundreds of years of intensive use. But it took a blend of the actual physical evidence, assessment of the ore and slags, the archaeological feature in the the smelting region, the archival operate, and reconstruction drawing to permit identification of the hundreds of years of interdependence of the two populations in this distant outpost.

Earlier studies of the composition of the slag at the web-site, by Hosler and some of her pupils, discovered that it experienced formed at a temperature of 1150 levels Celsius, which could not have been realized with just the blowpipe technique and would have needed bellows. That allows to ensure the ongoing operation of the web-site lengthy into the colonial period, Hosler claims.

Decades of operate went into trying to obtain methods to day the different deposits of slag at the web-site. The workforce also experimented with archaeomagnetic facts but found that the technique was not effective for the products in that certain location of Mexico. But the composed historical document proved key to building perception of the vast assortment of dates, which reflected hundreds of years of use of the web-site.

Files despatched back again to Spain in the early colonial period described the availability of the locally developed copper, and the colonists’ profitable checks of making use of it to forged bronze artillery items. Files also described the bargains designed by the indigenous producers to gain economic privileges for their men and women, dependent on their specialised metallurgical awareness.

“We know from documents that the Europeans figured out that the only way they could smelt copper was to collaborate with the indigenous men and women who were being previously undertaking it,” Hosler claims. “They experienced to reduce promotions with the indigenous smelters.”

Hosler claims that “what is so intriguing to me is that we were being in a position to use common archeological solutions and facts from products assessment as perfectly as ethnographic facts” from the furnace in a museum in the region, “and historical and archival material from sixteenth century archives in Portugal, Spain, and Mexico, then to set all the facts from these distinct disciplines jointly into an rationalization that is totally sound.”


The research been given guidance from Charles Barber, CEO of Asarco the Wenner-Gren Basis FAMSI and MIT’s Undergraduate Investigate Possibilities Plan.

Paper: “Copper smelting at the archeological web-site of El Manchón, Guerrero: From indigenous apply to colonial-scale production.” hundred and five