Ian Payne is Leading Britain's Conversation.
How did ‘X’ become a signal for a kiss?
Qualification: Study Saxon history
Answer: Before we used the modern alphabet, the Saxons and the Vikings used runes and carved them onto sticks and stones straight lines. Their letter X is a love rune. Each of their rune’s has a name. The X is called gyfu i.e. gift. If you are carving a love rune on a stick you would put X’s on it. That’s how I believe we get the letter X.