Researchers have delved into the ancient past to discover when romantic kissing likely originated and the pathogens, such as the herpes simplex virus, that have followed the practice from then until now.

Troels Pank Arbøll and Sophie Lund Rasmussen examined cuneiform writings from Mesopotamia, modern-day Iraq and Syria, looking for references to kissing.

The pair differentiate between two types of kiss: the “friendly-parental” kiss and the “romantic-sexual” kiss. The former is the kind of kiss a mother gives her child when she drops them off at school and, say the researchers, is seen in humans across time periods and the world. The second is not culturally universal. It’s thought that the sexy smooch evolved as a way of evaluating a potential mate through chemical cues communicated in saliva or breath, eventually leading to the sexual act.

Recent studies have suggested that the first known record of romantic kissing is on a Bronze Age manuscript from India, tentatively dated to 1,500 BCE. Arbøll and Rasmussen disagree, based on what they found in their study of Mesopotamian writing.

Cuneiform writing was first developed in Mesopotamia by the ancient Sumerians around 3,500 BCE. The researchers found references to kissing in texts dating from 2,500 BCE onwards. In the earliest Sumerian texts, kissing and sex often were described together.

Arbøll and Rasmussen found clear examples demonstrating that kissing was a part of romantic intimacy, whether the people doing the kissing were married or unmarried. They point to two examples featured in texts from around 1,800 BCE. In one, a married woman is almost led astray by a kiss from a man. In the other, an unmarried woman swears to avoid kissing and sexual relations with a specific man.

In addition to examining the history of kissing, Arbøll and Rasmussen also looked at the act’s unintended role in spreading oral disease. Once again, they turned to cuneiform texts in search of references to disease, aided by paleogenomics.

The advent of paleogenomics, the reconstruction and analysis of genomic information in our ancestors, has enabled the detection of herpes simplex virus 1 (HSV-1), Epstein-Barr virus, and human parvovirus B19 in ancient human remains. A 2022 study found that ancient HSV-1 genomes – that’s the virus that causes cold sores – were present on the teeth of human skeletons dating from 253 to 1,700 BCE.

The researchers found references in the ancient texts to a disease called bu’šānu, which resembles HSV-1 infection. The main similarity is the symptom that accompanied the disease, bubu’tu, which might be interpreted as “vesicle.” Vesicles are thin-walled sacs filled with fluid and, when found in or around the mouth, are a hallmark of HSV-1 infection.

The researchers say that their study of cuneiform texts reveals that kissing was happening far earlier, and in a far wider geographical area, than was first thought.

“The sources from ancient Mesopotamia suggest that kissing in relation to sex, family, and friendship was an ordinary part of everyday life in central parts of the ancient Middle East from the late 3rd millennium BCE onward,” said the researchers. “Furthermore, the sources from Mesopotamia show that the romantic-sexual kiss was known far earlier, and in a wider geographical area, than the references from India dated to 1,500 BCE, which stands in contrast to previous observations about the history of kissing.”

They also say that kissing and oral disease have long been associated.

“Evidence indicates that kissing was a common practice in ancient times, potentially representing a constant influence on the spread of orally transmitted microbes, such as HSV-1,” the researchers said. “It therefore seems unlikely that kissing would have arisen as an immediate behavioral adaptation in other contemporary societies, which inadvertently accelerated disease transmission.”

The study was published in the journal Science.

Source: AAAS via EurekAlert!