There are a number of theories about the origins of this tradition, including it being a hangover from the Romans’ Saturnalia celebrations or wintertide fertility rituals of the druids. Perhaps the most charming idea derives from a Viking myth of Frigg, goddess of love and marriage, and her ill-fated son Balder. Balder was so beloved that all things on earth – including living creatures, elements, metals, sicknesses and plants – were persuaded by Frigga to take an oath never to harm him.
Envious of his invincibility, the god Loki sought the one thing that had been overlooked – the tiny mistletoe – and contrived to have a deadly dart of the plant thrown at him. Devastated, Frigg declared mistletoe a symbol of peace and love, promising to kiss any who walked under it so that he might be remembered.
Whatever the true origin, kissing under the mistletoe was certainly an established Christmas custom by the early nineteenth century. In his short sketch Christmas Eve (1820), Washington Irving described ‘the mistletoe, with its white berries, hung up, to the imminent peril of all the pretty housemaids.’