Given the sales figures, the oft-asserted claim that Valentine’s Day is merely the brainchild of entrepreneurial florists doesn't appear too far-fetched. In recent years, some EUR 120 to 130 million has been spent at German florists alone around 14th February – fully twice as much as on other days. But the true roots of the practice are of a far more emotional nature. According to legend, back in the 3rd century AD, Italian Bishop Valentine of Terni agreed to marry soldiers even though state law insisted that they had to stay unmarried. As a consequence, so the legend goes, the “bishop of affection” was hanged on the 14th of February. Since then, the date has been associated with love and lovers and celebrated with poems, individually decorated cards and later also small gifts. Flowers and pre-printed greeting cards only became popular after the Second World War. Even so, many people are now harking back to the original tradition.

Declarations of love such as these immediately get the mind racing. For who wouldn’t like to receive words such as these? Or even pen them? A love letter is like a ticket to a hidden world of emotions, a carefully formulated revelation of previously closely-guarded secrets. In an age in which everything is distributed en masse through likes and retweets, words written for only one person – the one person – can be almost breathtakingly intimate. They are also wonderfully luxurious, given that a hastily typed “X” is often the closest thing we get to expressing affection nowadays.

“I know many young women who receive many e-mails and text messages, but never a letter written with feeling,” says British author Jojo Moyes, whose best-selling novel ‘The Last Letter from Your Lover’ tells the story of a young journalist who stumbles across a love letter in her newspaper's archives.  The story is fictitious, but the quotations that open each chapter are genuine: while writing her book, Moyes advertised and asked online for people to submit declarations of love from real life. The letters she received were full of passion, pain and humour, but also despair, such as this one: “I wish I could be the person who rescues you, but that simply won’t happen.”

But it's better to be really frustrated than artificially jolly. Authenticity is everything, says Swiss linguist Eva Lia Wyss, who has collected and analysed more than 7500 love letters in Zurich University’s “love letter archive.” She believes that hardest love letters to read are those taken from preset texts or literature. After all, the detached copy-paste principle is the polar opposite to how we are actually feeling. “Letters are often written when people are getting to know one another or developing a relationship. That’s mostly the most passionate time,” she says.

An article entitled ‘Liebe auf den ersten Block’ (Love at first pad), published in 1001 magazine by the German Journalist’s School in Munich, tells the story of a very special budding relationship: when Achim, a young German tourist, meets an Italian woman called Pina near Rimini in 1959, the two immediately strike up a friendship – yet don't have a common language in which to communicate. So they buy dictionaries and writing pads and proceed to master each other’s language and culture syllable by syllable, falling in love in the process. “I love you non per 14 giorno, sempre, sempre,” Achim notes. He is proven right: almost 60 years later, he and Pina are still together.

Perhaps that's because he followed the advice of a very famous writer quoted in the first volume of the wonderful and now cult collection “Letters of Note” (compiled by Shaun Usher): in 1971, actor and future US President Ronald Reagan wrote his stepson a very personal letter of congratulation on his wedding day. It ends with the words, “p.s. You'll never get in trouble if you say, 'I love you' at least once a day.”