The symbol progressed to become known as a sign of love. In the Middle Ages, a lot of people couldn't read or write. When they had to sign a document, they would make an X in place of their name. In front of witnesses the signer would kiss the X to show themselves trustworthy. Found in Africa, these brightly colored birds sit very close together with their mates, earning them their name.
Doves are also part of the tradition.
They are symbols of love and loyalty because they mate for life. A pair of doves will also share the care of all their babies. A love knot is a symbol of everlasting love, because its winding loops have no beginnings or ends. In times past, they were made of ribbon or drawn on paper to prove ones undying love. Valentine's Day and Mother's Day are the biggest holidays for giving flowers.