Last week, I had a stroke of luck. A friend had invited me for a weekend away in Barcelona and when I checked out the dates, I realised something very exciting: our visit would coincide with Diada de Sant Jordi, the festival day of Catalonia’s patron saint and one of the biggest book parties on the planet.

Dating back to the Middle Ages, the celebration originally centred around lovers giving each other roses, drawing on the legend of Sant Jordi and the dragon, from whose blood a rosebush is said to have sprung. Then, in the 1920s, a member of the literary community in Barcelona (can anyone tell me his or her name?) noticed that the death dates of Shakespeare and Cervantes also fell on April 23. Inspired by this coincidence, the wordsmith encouraged people also to exchange books on this day – an idea which rapidly caught on.

The rest, as they say, is history. These days, thanks to the hundreds of stalls set up in the streets each Diada de Sant Jordi, the festival accounts for as much as 8 per cent of the book sales that take place in the region every year. The extravaganza has been such a success that it even inspired UNESCO’s World Book and Copyright Day.

You can imagine my excitement at being in the midst of it. While my companions slept off the journey, I was up early and out exploring the streets.

Even at 8am, many parts of the city were buzzing. On Rambla de Catalunya – one of the major centres of the festival – two rows of stalls stretched at least a quarter of a mile, laden with roses and books.

All the major booksellers and publishers in the city had a presence. Wandering through, I spotted impressive spreads from Altaïr, BCN Books and La Central, to name but a few, as well as numerous stands devoted to specialist areas – from cookbooks to crime.

The offerings were extensive, featuring huge numbers of works by local and international authors. Titles by the celebrated Catalan writer Jaume Cabré were much in evidence, but I also saw numerous Spanish and Catalan versions of a number of old favourites and familiar faces from further afield.

There was Pétronille by Amélie Nothomb and La perla by John Steinbeck; both La noia del tren and La chica del tren by Paula Hawkins, and Roald Dahl’s Charlie y la fábrica de chocolate. Bestselling Italian writer Umberto Eco’s Il nome della rosa appeared here as El nombre de la rosa, while Helen MacDonald’s H is for Hawk was reconfigured as H de halcón (the Catalan version, which renders the title F de falcó, has just come out). And on several stands there teetered stacks of translations of the works of Jo Nesbø and EL James – some of them easily high enough to kill a toddler should they happen to fall.

Perhaps the most surprising title I saw was a Spanish translation of London Mayor Boris Johnson’s biography of Winston Churchill. No book, it seemed was too niche for Sant Jordi.

By contrast, the small handful of second-hand English-language titles I discovered on one table, looked rather sad. Although I did find the presence of Ernest Hemingway’s Death in the Afternoon, his memoir of the time he spent observing bullfighting in Spain, rather fitting. (The selection of ‘Livros en alemán’ was rather better.)

In addition to the books, authors were out in force too – or were certainly scheduled to be, judging by the number of boards promising signings later in the day.

There was no doubt about it: literature was a major focus here. However, seasoned literature professionals were by no means the only ones plying their wares.

I spied a stand devoted to books of piano scores – including the soundtrack for Frozen – and another offering colouring books. There were significant numbers of political organisations peddling texts supporting Catalan independence. Some even had televisions broadcasting their messages into the street. There was a stand run by a youth organisation that looked very much like the scouts, and numerous stalls raising money for charities such as Oxfam, the Red Cross and Save the Children.

Manning and womanning many of the stalls – and sometimes dashing out into the thoroughfare to thrust roses and leaflets at passers-by – were various costumed figures. I lost count of the number of dragons I saw and there was a healthy showing of Sant Jordis and princesses too. Other folk had gone for a more minimalist approach, simply draping themselves in the Senyera (Catalonia’s flag).

The roses were by no means all orthodox either. They came in a huge variety of shapes, sizes and materials. There were rose lollipops and pendants. There were key rings and desk tidies. By one crossroad, I spotted a woman selling some intricate, free-standing blooms sculpted out of metal. Nearby, another vendor was driving a hard bargain for flowers fashioned from tiny bits of coloured plastic melted together in the oven.

Overall, the experience was exhilarating (although I was pleased to have got there early and beat the crowds, which made browsing the stalls very difficult later in the day). I made my way back to our apartment in time for brunch, sporting a handful of bookmark roses and a very large grin.

Feliç Diada de Sant Jordi!