FACTBOX: Origins of Valentine's Day

(Reuters) - Valentine's Day will stoke the embers of romance worldwide on Thursday.

Here are some key facts on the day and its origins.

* POSSIBLE ORIGINS

-- Although there were several Christian martyrs named Valentine, the day probably took its name from a priest who was martyred about AD 270 by the Roman emperor Claudius II Gothicus.

According to legend, the priest signed a letter to his jailer's daughter, with whom he had fallen in love, "from your Valentine."

-- The day may also have originated in the ancient Roman celebration of the Feast of Lupercalia in honor of Juno, the queen of the Roman gods and goddesses, on February 14. Juno was also the goddess of women and marriage so honoring her was thought to be a fertility rite.

-- At the feast held the next day, the women would write love-letters and stick them in a large urn. The men would pick a letter from the urn and for the next year, pursue the woman who wrote the chosen letter. This custom lasted centuries.

* THE FIRST CARDS

-- The custom of exchanging cards and other tokens of love on February 14 began to develop in England and France in the 14th and 15th centuries and became especially popular in the United States in the 19th and 20th centuries.

-- In England in 1477 Margery Brews sent a letter to her fiance, John Paston of Norfolk addressing him as "my right wele-belovyd Voluntyn".

-- In the United States the first commercially produced cards were manufactured by Robert H. Elton of New York in 1834.

* VALENTINE'S DAY EVENTS

-- Since 1994 couples have been married on the 80th floor of the Empire State Building.

-- In 2002 two male and six female elephants were married at a ceremony in the ancient Thai capital of Ayutthaya, though one pair just did what comes naturally. "It is rather tricky trying to stop a 16-year-old elephant groom from consummating his marriage before the ceremony," said one of the organizers.

-- In 2003 the Galeries Lafayette department store in Paris invited those seeking instant love to a marathon-dating session on February 13 for seven-minute tete-a-tetes with seven potential partners.

-- In 2006 hardline Hindu groups and radical Muslims burned Valentine's Day greeting cards and held protests across India against celebrating the festival of love, saying it was a Western import that spread immorality.

Sources: Reuters/www.britannica.com/www.history.com/Famous First Facts

(Writing by David Cutler, London Editorial Reference Unit. editing by Paul Casciato)