Valentine’s Day Word Origins
Cupid, in Roman Mythology, is the god of love. He was said to be the son of Mercury and Venus. (Cupid's Greek counterpart is Eros.) In Latin, the name was Cupidines, a personification of cupido, "desire, love" (from cupere, "to desire or long for").
Heart can be traced back from Old English (c 725) and has cognates in Old Frisian, Old Saxon, Middle Dutch, Old High German, Old Icelandic, Danish, Norwegian, and Gothic back to Proto-Germanic. The spelling was herte until about 1500 when it was spelled heart by analogy of pronunciation with heat, stream, etc. The Indo-European root is shared with Latin cor, cord- and Greek ker, kardia. As the seat of feeling and intellect, heart has been used since around 825.
A Valentine as a sweetheart, lover, or special friend was first written about c 1450. Originally, it meant such a person chosen, drawn by lot, or otherwise determined for the upcoming year. Valentine as a card (c 1553) was at first a folded paper inscribed with the name of the person chosen or drawn as a valentine. By 1610, the word also referred to a gift given to the special person. The use of the word to mean "a written or printed letter or card with decoration, verse, etc. of an amorous nature" sent or given on St. Valentine's Day began around 1824. The word can be written with an initial capital or without.
The oldest known valentine still in existence today was a poem written by Charles, Duke of Orleans to his wife while he was imprisoned in the Tower of London following his capture at the Battle of Agincourt. The greeting, written in 1415, is part of the manuscript collection of the British Library in London, England.