12 things you never knew about kissing but you really should.

4. The History Of “X” Being Used As A Symbol For A Kiss Goes Back To The Middle Ages

Reportedly, illiterate people in the Middle Ages used to sign their names with an X and then kissed it to seal the signature. Today, we often use XOXO as written symbols of both hugs and kisses. We often sign letters and cards by adding XOXO before our signatures. Today everyone knows what XOXO stands for, but most people do not know where it originates from.

Several historians have traced the affectionate custom back to the Middle Ages when people, who could neither read or write, signed their names on documents with an X, then kissed it to show their sincerity.