On February 14, the western world celebrates Valentine’s Day. The holiday may be named for one or more martyred third-century saints, but its origins are a bit murky. It didn’t become a day for lovers until centuries later. Some experts trace the association with romance to Geoffrey Chaucer, who, in his 14th-century poem “The Parlement of Foules,” wrote that birds choose their mates on Valentine’s Day. The tradition of expressing love on Valentine’s Day began in Europe in the Middle Ages and grew in popularity with the advent of mass-produced Valentine’s Day cards in the 19th century. Today, Americans exchange an estimated 145 million Valentine’s Day cards every year—and that’s not including the packaged kind students often trade in school. Valentine’s Day traditions vary from country to country. Chocolate is a popular gift, as are flowers. In the Philippines, local governments host mass wedding ceremonies on Valentine’s Day, sometimes with hundreds of couples. In South Africa, some women pin the name of their partner or crush to their sleeve. In some more conservative countries, however, publicly celebrating Valentine’s Day is discouraged or banned.