Saint Valentine was a Roman martyr and priest, died in 270. His name has come to be associated with a pagan celebration in honor of love on February 14. He is regarded as the patron saint of unhappy lovers, and love messages generally sent on Feb. 14 are called Valentines after him.
According to the legend, St. Valentine was beheaded on February 14, at Rome, under Claudius II. The old notion was that birds began to mate on that day, and hence arose the custom of young persons of both sexes choosing each other as " Valentines" for the ensuing year by a species of lottery, and of sending love missives to each other.
Also a letter or other missive sent by young persons of both sexes to each other on Valentine's day; a printed missive of an amatory or satirical nature, generally sent by post anonymously. Some Valentines are highly ornamental and artistic, while others (commonly called " comic Valentines") are caricatures, designed to reflect on the personal appearance, habits, and character of the persons to whom they are addressed.