In 1382, Geoffrey Chaucer wrote his poem Parlement of Foules. The poem contains the first recorded instance of St Valentine's Day being linked to romantic love.

"For this was on seynt Volantynys day
Whan euery foul comyth there to chese his make."

Some argue that Chaucer was talking of May time when birds are more likely to mate in England. This coincides with the feast of St Valentine of Genoa that falls in May.

• In the 15th century, 14 February became an annual feast day in France. Banquets with singing and dancing were held to celebrate romantic love.
• During this time, a Frenchman, imprisoned in the Tower of London, wrote the earliest surviving Valentine's greeting to his wife. "I am already sick of love, my very gentle Valentine."
• By the 17th century, Shakespeare mentions Valentine's Day in Hamlet. "To-morrow is Saint Valentine's day, All in the morning betime, And I a maid at your window, To be your Valentine."
• In the 18th century, the most famous Valentine's poem was found in a collection of nursery rhymes. "The rose is red, the violet's blue, The honey's sweet, and so are you."

The first Valentine's day cards were sent in the 18th century.

Initially, it was handmade cards. Lovers would decorate paper with romantic symbols like flowers and love knots. It often included puzzles and lines of poetry. These cards were then slipped secretly under a door, or tied to a door-knocker. Pre-printed cards initially appeared in Georgian Britain, although they only became popular later on.

In the early 19th-century, the industrialisation of Britain brought with it advances in printing and manufacturing technologies. Mass-produced Valentine's cards became very popular.

A collection of over 1,700 cards is still held at the Museum of London. Cards feature elaborate paper lacework, embossing, and other intricate designs. Typical imagery includes flowers, love knots, and cupid. Hearts were sometimes used, but the Victorian cards did not feature red hearts like they do today.

The less loved-up bought 'Vinegar Valentines' to use as an insult. These cards typically poke fun at a man's profession or a woman's appearance.

One example is a card that features a cartoon of a woman with a large nose. It reads:

"On account of your talk of others’ affairs
At most dances you sit warming the chairs.
Because of the care with which you attend
To all others’ business you haven’t a friend."

In the mid-19th century, Valentine's cards gained popularity in America, where they were first advertised as a British fashion.

In 1913, Hallmark Cards produced their own Valentin's card, representing a key development in Valentine's Day's commercialisation. Today Valentine's Day also includes buying flowers, jewellery, perfume, and chocolates.