A corruption of galantin (a lover, a dangler), a
gallant. St. Valentine was selected for the sweet-hearts' saint
because of his name. Similar changes are seen in gallant and valiant.
One of the Two Gentlemen of Verona; his serving-man is Speed. The
other gentleman is Proteus, whose serving-man is Launce. (Shakespeare: Two Gentlemen of Verona.
in Congreve's Love for Love. Betterton's great character.
Valentine (The Brave).
Brother of Orson and the son of Bellisant, sister of King Pepin and
wife of Alexander, Emperor of Constantinople. The twin brothers were
born in a wood, near Orleans, and while their mother went in search of
Orson, who had been carried off by a bear, Pepin happened to see
Valentine and took him under his charge. He married Clerimond, niece of
the Green Knight. (Valentine and Orson.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894