Which duke wrote the oldest known Valentine's message while imprisoned in the Tower of London?

Charles, Duke of Orléans wrote the oldest known surviving Valentine's message while imprisoned in the Tower of London.

Charles was captured by the English after the Battle of Agincourt in 1415, one of the most famous English victories of the Hundred Years' War. He remained an English prisoner for about 24 years, living in several castles and composing poetry during his captivity.

The surviving message is a rondeau addressed to his wife. It is often described as the earliest surviving valentine, although it was a poem rather than a mass-produced greeting card. The wording also reflects the medieval tradition of courtly love, which predates the modern commercial holiday by centuries.

A common mix-up is confusing Charles with Henry V, who fought at Agincourt, or with later English prisoners. Another milestone came in 1477, when Margery Brews wrote one of the earliest surviving valentines in English to John Paston. The modern association between Valentine's Day and romantic love is generally linked to Geoffrey Chaucer's 14th-century poetry.