Kissing’s a strange thing. We tend to think it’s innate, that it’s natural for humans to do it – but it’s not. There are still cultures today where kissing is not done at all.
I know very little about non-Western kissing, other than that it appears in early Indian texts and seems to have been present in Ancient Egypt, too. It appears in Ancient Greek texts as far back as the 9th century BC.
But it was the ever-passionate Romans who really brought kissing to Europe.
Kissing played a central part in Roman culture. They even had different words for different types of kiss: osculum, savium, and basium.
Osculum: The osculum (“little mouth”) kiss was a non-sexual kiss. Kissing was a big part of family life in Ancient Rome, and relatives often kissed each other on the lips as a form of greeting (presumbly with closed mouths, based on the name.) There was an ancient tradition, the ius osculi, by which women were permitted to kiss their relatives on the lips when seeing them for the first time that day. This was allowed up to the sixth degree of relation, and apparently extended to the husband’s family, too. Kissing amongst brothers and sisters was expected, though ‘not too often.’
Occasionally, people would refuse to kiss their relatives as a way of saying they no longer saw them as family.
Platonic kissing extended beyond the family: it seems friends sometimes greeted each other with kisses. Interestingly, kissing was also a big part of the business and legal world: illiterate people could seal an agreement with a kiss on the lips (as opposed to a signature or handshake), which may be the source of the Medieval tradition of sealing knighthoods or oaths with kisses on occasion. Weddings were also sealed with a kiss, presumably both because kissing was expected between couples and because they were sealing the agreement: the wedding kiss has survived to the modern day.
Kisses were also used to seal letters. They really loved to kiss!
Savium: The savium seems to have been a more illicit, sexual type of kiss. In the early period, it was used specifically in a sexual or low-register context, and may have described the erotic kiss between lovers. In the later period, however, it became a more accepted word for general kissing, and its role was replaced by Basium.
Basium: Appearing after savium became generalised, basium was another word for the romantic or lover’s kiss. Though it, too, eventually became more generalised, it seems to have remained a more informal or casual word for kissing, and was never used in ‘refined’ prose.
After the fall of the Romans, kissing faded across Europe, though we still see references to Medieval people kissing as general greetings or at ceremonies like knightings.
It experienced a rebirth with the rise of courtly love in the 1100s. From then on, the kiss assumed a more erotic reputation in the West, and kissing on the lips became less common amongst friends and family. This process has accelerated in recent times, especially in the UK and North America, where platonic kissing has become a rarity, especially amongst men.