Archaeologists at the British Museum have discovered what they believe are examples of the world’s oldest tattoos, according to NPR. The two mummies — one male and one female — have been in the Museum’s possession for over 100 years. Nevertheless, experts have only recently been able to identify the strange markings on their bodies.

Initially, scientists thought the markings were “meaningless smudges,” having little historical significance. It wasn’t until Oxford professor Renee Friedman thought to use infrared cameras to examine them. Funnily enough, Friedman was using the cameras to work on an unrelated project. “I said, hmm, why don’t I try my little camera on these well-preserved bodies,” she told NPR.

The female had a pattern of four repeating S-shapes along her right shoulder. Friedman told NPR, “Those marks are known from the contemporary pottery at the time, though we don’t know what it means.” Friedman went on to say, “…her markings are more associated with cult knowledge, knowing the proper moves, knowing the proper rituals and spells.”

According to BBC News, scientists say the male died of a stab wound when he was between 18 and 21 years old. They found he had dark smudges on his arm like the female, which they thought nothing of. To their surprise, the infrared scan revealed them to be tattoos, described as “two slightly overlapping horned animals.”

Friedman said finding tattoos on a male was unusual for the time. According to many Egyptologists, tattoos were most commonly a trend that women followed. Finding the tattoos on a male of the time, however, “was a real game changer in our perceptions of tattooing,” Friedman said.

Researchers believe the tattoo ink was most likely soot. Since it was picked up by the infrared cameras, the ink is likely to be carbon-based.

Friedman believes the tattoos, like in modern times, were meant as either decoration or for expression. “They’re in parts of the body that would’ve been on daily display,” she said. The fashion climate at the time including “colorful clothing, they had colorful leather. They probably looked fabulous.”

According to British Museum curator Daniel Antoine, in an interview with Smithsonian, the tattoos give more evidence to what life was like for these individuals back then. Known as “Gebelein Man A” and “Gebelein Woman” (named for the region of Egypt they were discovered), the mummies are estimated to have lived between 3351 and 3017 BC. Antoine believes that time will indicate “their status, their preoccupations, their special knowledge.”

Amazingly, BBC News pointed out how the mummies were not given any special treatment in their burial. They were placed in shallow graves without traditional mummification or preservation, but were well kept thanks to the heat, salinity, and dryness of the desert. However, under different conditions, it’s likely the two never would’ve lasted as long as they have.