The Sicán culture was one of the major Pre-Incan civilizations of modern-day Peru. Seven hundred years have wiped away most knowledge of the Sicáns, but the elaborate gold objects retrieved from tombs tell us much of what we do know. One new insight has been offered through chemical analysis of the paint on a 1,000-year-old gold mask that turns out to contain human blood and bird egg proteins.
The Sicán culture survived for at least 500 years. An impressive tomb from the Middle Sicán Period (1,100-900 years ago) managed to survive undisturbed beneath the Huaca Loro temple until the early 1990s, while many counterparts were looted. It was the first elite Sicán tomb from the Middle Period to be scientifically excavated. When a team of archaeologists entered it they found a male skeleton around 40-50 years of age upside down and painted red at the center of the chamber, with the skeletons of two females and two children around it.
Among the items in the tomb was a gold mask painted red and covering the man's detached skull, which unlike the rest of him was right-way-up. An analysis of the chemical composition of the paint has been published in the American Chemical Society's Journal of Proteome Research.
The red color was initially identified as cinnabar, a mineral commonly used by the Sicáns for high-status people and objects. The less privileged made do with iron oxides and tree resin. However, from the beginning archaeologists recognized cinnabar would not stick to gold without a binding agent over such a vast span of time. Determining the binding agent originally proved too difficult, but now a team led by Oxford University's Professor James McCullagh, undeterred by a terrified half the world telling them to put it back, have performed infrared analysis. This revealed the presence of proteins, which were eventually found to be from a mix of human blood and the whites of birds' eggs. It is thought the same mixture was used to color the skeleton as a whole.
The entire tomb appears to have been carefully arranged, suggesting every positioning, and therefore probably every object, was imbued with deep significance. For example, the two female skeletons are positioned as if one was giving birth and the other acting as midwife. The children's skeletons crouch on a higher level.
The tomb included 1.2 tons of grave goods, around a third of them metal, testifying to the enormous wealth and status of the upside-down man. However, even amongst all this finery, the mask stood out.
The findings may be useful to those who want to bind inorganic pigments to gold for 1,000 years, but the authors think there is probably more significance to the choice than merely finding something sticky.
“The unique inverted placement of the skeleton next to the two young adult women in parturition and midwifing poses suggests that the desired effect was the rebirth of the deceased leader,” the paper notes, and red oxygenated blood probably symbolized the “life force”. Life force was reserved for the privileged, however; the paper notes Sicán sacrificial victims were cut at the neck to maximize bleeding.