In the Middle Ages, all of Europe was kissing. However, the practice was governed by one's rank.
People of equal rank, both male and female, would kiss on the lips; people of lesser rank would kiss one's cheek, hand, knee, foot or the ground in front of the person.
"The greater the rank difference, the further from the lips one would kiss that person," Bryant said.
As many did not know how to read and write, a kiss was also used to seal contracts. People drew an "X" for their name on the document and kissed it to make it legal. That's the origin of the X put on Valentines or letters to symbolize a kiss.
By the 1300s the Catholic Church became greatly concerned about kissing, fearing that it would lead to carnal acts.
At the Council of Vienna in 1311-1312, Pope Clement V forbade the so-called "holy kiss" during church services. Still today, a handshake is used as a gesture of peace in Catholic Church in place of the holy kiss.