19. In the Middle Ages, the illiterate masses would sometimes sign their name with an X, and this became an affectionate sign-off
And why do we sign our Valentine’s Day cards (and text messages and emails) with an X? The letter has been used to symbolize a kiss ever since the Middle Ages. Quite why is open to debate. Some historians maintain it’s because an X looks like a cross, and therefore was seen as a symbol of the love of Jesus. However, others argue that it’s simply because back in the Dark Ages, few people were literate, and most couldn’t even write their own name. So, when they needed to sign a document, they would simply put an X at the bottom – and so, a tradition was born.
