Among Canterbury Cathedral’s architectural wonders are its ornate, centuries-old stained glass windows. It is now clear that some of the windows are even older than originally thought. In the thirteenth century, 86 panels, each depicting an ancestor of Christ—known as the “ancestor series”—were installed along the cathedral’s clerestory as part of a major restoration after an 1174 fire. Experts noticed decades ago that four of those panels appeared to be of an earlier style. It is notoriously difficult to date stained glass since doing so normally requires the windows to be dismantled. Using a portable X-ray fluorescence machine equipped with a specially designed attachment, a team from University College London was finally able to date the glass panels by analyzing their chemical signatures. “This study was the first real test of this in situ methodology that we developed for medieval stained glass,” says archaeologist Laura Ware Adlington, “and the success we’ve experienced far exceeds our expectations.”

The team determined that the panel showing the prophet Nathan, and likely those showing three others, are significantly older than the rest. They date to the 1130s, and are among the oldest stained glass windows in the world. The researchers believe that these early glass panels were originally located in the cathedral’s choir and survived the fire. Almost a century later, they were incorporated into the ancestor series. “Of course, we can’t help but get excited by words like ‘oldest’ and ‘earliest,’ but it is more than that,” says Adlington. “In this case, the windows are survivors of a fire, relics of a former cathedral that is no longer there, but which has left clues behind about its appearance.”

During the Japanese occupation of China in 1933, a man working on a bridge in the city of Harbin in the northeastern part of the country discovered a skull and immediately hid it from his Japanese overseers. In 2018, the elderly man revealed his secret to his grandchildren, who recovered the skull from the abandoned well where the man had concealed it 85 years earlier. They turned the skull over to scientists at the Geoscience Museum of Hebei GEO University. The researchers determined that the skull is at least 146,000 years old by using uranium series dating, which examines trace amounts of uranium and thorium in bone. Since uranium decays to thorium at a known rate, they were able to calculate the skull’s age from the ratio of the two elements. The skull has a unique mixture of traits associated with Homo erectus, such as a massive brow ridge and low forehead, and traits that appear only in more recent hominins, such as a relatively small face and large brain. The skull could possibly represent a previously unknown human lineage, says Chris Stringer of London’s Natural History Museum. Stringer’s colleagues have named the species Homo longi.

According to Stringer, it is also possible that the Harbin specimen may belong to the same species as the Denisovans, a lineage closely related to Neanderthals that is only known from a few small bones and a complete DNA sequence. In order to test this possibility, DNA would have to be recovered from the Harbin skull. Stringer points out that another fragmentary fossil skull, found at the site of Xuchang in central China, may represent yet another separate hominin lineage dating to about 100,000 years ago. If that it is the case, there may have been at least four different lineages of early humans in China at that time—Neanderthals, Homo sapiens, Homo longi, and the Xuchang hominin. “You’ve got all these different experiments in how to be human,” says Stringer, “and Harbin adds one more.”

Beginning sometime between the sixth and fourth centuries B.C. and continuing up until the late twentieth century A.D., members of rural communities sporadically worked the Chehrabad salt mine in northwestern Iran. Since 1993, archaeologists have uncovered the remains of eight ancient miners whose bodies were mummified by the mine’s salt-rich and low-moisture environment, along with mummified animal remains, including a sheep’s leg that was discarded some 1,600 years ago. “The mine’s extremely dry conditions quickly desiccated the sheep’s soft tissue,” says Trinity College Dublin geneticist Conor Rossi. “Its DNA was extremely well preserved.”

Examining the sheep’s DNA has allowed Rossi and his colleagues to envision what the animal looked like. The scientists identified a gene associated with a fat tail, a characteristic still present in sheep raised for their meat in the area today. They also determined that the sheep did not have the genetic mutation associated with woolly fleece, which was an important commodity starting in the mid-to late fourth millennium B.C. Scanning electron microscopy of hair fibers preserved on the animal’s leg confirmed that this particular sheep likely had a hairy rather than a woolly coat. Given these traits, the researchers believe ancient miners consumed the sheep for its meat. Says Rossi, “This sample builds up a bigger story about how ancient people used specialized breeds of animals in thoughtful ways.”