TODAY is Valentine’s Day. It’s that time of year when we all go mad over roses, chocolates and hearts.

Yet again, commercial interests have taken over a day of our lives and we spend a fortune buying cards, paying inflated prices in restaurants, buying jewellery, or booking romantic getaways.

This week, my wife and I are in Porto, Portugal. How romantic, you’re thinking. Well, not quite. We are actually working, attending a science education conference.

While walking around Porto, we’ve been struck by quite how different it is here. We don’t see hearts everywhere, signs in restaurants urging people to book a table for Valentine’s Day or jewellers trying to sell Valentine’s necklaces, rings and bracelets.

So what is this day really all about and why did it come into existence? It’s clearly all because of St Valentine. Saying that, we should determine which Valentine we are talking about, which date we should celebrate and why. There were a number of Valentines in the Church who became martyrs. What is not commonly known is that more than one Valentine could be celebrated. The first and most widely known is Valentine of Rome, a priest martyred in 269AD.

He was imprisoned and sentenced to death for various “crimes”, such as providing ministry to persecuted Christians, performing marriages for soldiers, who in those days were forbidden to marry. In part, he became a saint apparently for restoring sight to the blind daughter of the judge who sentenced him to death for his crimes. Legend has it that the priest wrote to the judge’s daughter on February 14 and signed his letter, “your Valentine”.

A second Valentine was Valentine of Terni, Bishop of Interamna martyred in 273AD. A third Valentine is thought to have been martyred in Africa, but very little is known about him, including whether or not he actually existed.

Although we know many Valentines existed, how one became associated with love and why we celebrate the day with gifts for our loved ones didn’t start with the note signed “your Valentine” (which may be no more than a convenient story to boost the myth of a saint devoted to lovers) but with the work of Geoffrey Chaucer in the 14th Century.

To celebrate the first anniversary of the marriage of King Richard II to Anne of Bohemia, Chaucer wrote a poem which contained the line “for this was on St. Valentine’s Day, when every bird cometh there to choose his mate.” Many people assume Chaucer was talking about St Valentine of Rome and the celebration taking place on February 14, but others claim Chaucer was probably making reference to yet another Valentine, St Valentine of Genoa who’s feast day is May 3 and who died in 347AD. Yet another Valentine to add to our list.

Valentine’s Day is also celebrated in July by other Orthodox Christian religions. As usual, our nice neat celebrations of days and feats are muddled and fluid, changed over time to suit different religions and different purposes.

Another legend says that Valentine’s Day is based on the ancient Roman festival of Lupercalia, which happened around the middle of February . This was a festival of fertility, but prior to Chaucer’s poem Lupercalia was never associated with Valentine.

The modern concept of Valentine’s Day as a celebration for lovers is really a British invention. In 1797 a book of suggested verses for young men to write to their lover was published and it was around this time that the first cards were being printed for people to send.

The day as a day for lovers grew in popularity in the 19th Century and factory based paper Valentine’s cards, sketches and verses became more popular. In 1835 about 60,000 Valentine’s cards were sent by post. Once the cost of postage became standardised, with the introduction of the penny black stamp in 1840, the number of cards sent by post increased to more than 400,000.

In 1868, Cadbury produced the first Valentine’s chocolates in a heart shaped box.

There is no doubt that Valentine’s Day is now fully commercialised, with more than a half the UK population exchanging gifts and cards with an annual turnover of over £2 billion pounds.

True love though is not shown through cards, chocolates, or even diamonds.

True love is a connection, an understanding, a feeling that can be difficult to put into words. It’s something you just know to be true.