New research suggests allies of the Aztecs ceremonially disfigured the bodies of captive Spaniards during one of the worst defeats in the Spanish Conquest of 1519-21.

The National Institute of Anthropology and History said Wednesday that the heads of captive Spanish women were strung up on skull racks alongside those of men. The women were pregnant, which in pre-Hispanic practice qualified them as "warriors."

One Spanish male was dismembered and burned to imitate the fate of an Aztec-era god. A female captive's body was cut in half.

The research came at the Zultepec-Tecoaque site, which was an Aztec-allied town that in 1520 captured a convoy of more than 60 Spanish men and women and allied fighters. Scientists say they were sacrificed, apparently over months.