Scientists Find Out Why the Terracotta Army's Weapons Were So Well Preserved

(Credit: lapas77/Shutterstock) To protect Chinese emperor Qin Shihuang in the afterlife, thousands of clay soldiers joined him underground some 2200 years ago. The discovery of this Terracotta Army in the 1970s was a great gift to archaeologists — and fans of "ancient lost technology" stories. The trope, which has some basis in fact, suggests that our ancestors were privy to some knowledge or technology that would still be useful, but has since been lost to the ages. When researchers discovered that this buried, ancient army of clay had remarkably preserved weapons, it was reasonable to wonder if the craftspeople at the time had treated them to avoid rust somehow. Chemical analyses showed that the arms contained trace amounts of the element chromium — an ingredient in stainless steel — and so for decades the thinking has been that Qin’s people had developed some cool kind of chromium-based anti-rust coating to put on their weapons. Well, new research appearing today in Scientific Reports shows that… maybe not so much. “The chromium anti-rust treatment theory should,” the international team of authors writes, “be abandoned.” The reasoning is simple: Chromium only appeared in a few weapons, had little to do with actual preservation and was likely related to an entirely different, and explainable, process. Instead, the authors propose some possible reasons for the weapon preservation that have actual evidence behind them.