Baroque towns, religious processions and a cuisine with an Arab accent make the Mediterranean’s largest island culturally distinct from the Italian mainland.

In Sicily, time has stood still like nowhere else. So many places in the world now somehow look the same, but here even the people haven’t been regularised as they have been elsewhere. Stop at Palermo’s main food market, the Mercato della Vucciria, one morning and you might see an elegant, aristocratic queen of a man in his seventies talking to a chap with a face like a prune about the price of anchovies. The market of Vucciria is just the same as it was when Renato Guttuso did his wonderful painting of it in the 1970s – the same intrigues, the same vibrant street culture, the same street cries. The stallholders are still screaming about how good their tomatoes are that day or, triumphantly: ‘We caught swordfish!’ It’s an incredibly noisy place – in the Sicilian dialect, the market town’s name translates as ‘voices’ or ‘hubbub’.

What’s for sale is whatever is good to eat that day; all fresh, seasonal stuff from around the island. Fish, for example, are displayed in rigor mortis – all curled up, not lying flat on the slab – to demonstrate that they’ve just been caught. When I was there last, I bought mulberries the size of bumblebees and great punnets of wild mushrooms for just a few quid. Cedro is a local citrus fruit that looks like a giant lemon. I used to see them in Italian still-life paintings and think, ‘Wow, lemons were bigger in the olden days,’ before I realised they were something different. Like a lemon with comparatively less of the juicy bit, the cedro is nine-tenths pith, but the pith is soft, slightly spongy and delicious. You won’t find green beans flown in from Kenya at the Mercato della Vucciria – all the produce sold here is from here. Of course this is the way we all used to eat, but in Sicily the tradition has remained.

Sicily is a taste of ‘old Italy’, but the reasons why it is so unchanged are actually quite sinister and dark. It’s to do with a history of extreme poverty and the stranglehold of the Mafia. Sicily’s deep sense of separatism has its legacy in the Spanish invasion of the island in the late 14th century. During its heyday, the Spanish empire sucked the island dry – people were treated as serfs and retreated inland to form their own, separate society. By the 19th century, this vagabond culture was completely entrenched, with the whole of Sicily being ruled by these nameless, shadowy figures who became the Mafia.

The Mafia is the idea of the family turned into an alternative political system. The notion that your family is what you cleave to – rather than the state – is an ancient one in Sicily because, traditionally, the island has been ruled by outsiders. More than anything else, what draws me to Sicily is the sense that it’s not really part of Italy or indeed anywhere else – it’s a place that represents all of culture. It has been affected by Africa, very strongly by the Arab world, the Normans, the Romans and the Greeks. Wherever you go in Sicily you’re reminded of the central truth of human civilisation, which is that there’s no such thing as national identity; the Sicilian approach is just not to have one. This is apparent in the island’s food. A fantastic dish like pasta con le sarde – pasta with sardines and raisins – has its roots in the Arab invasion, with a sweet and sour taste that you will find nowhere else in Italy.

Sicily’s capital Palermo is a layer cake, each tier representing a different outside influence. Walking its streets is like travelling through time. The Cappella Palatina, or Palatine Chapel, is an extraordinary blend of Norman, Byzantine and Arab art, and a few streets away is the castle of La Zisa, built for a Norman king by Arab craftsmen. The post office is one of my favourite buildings – a huge, white, Neoclassical fascist temple, now a monument to Mussolini’s failed experiment to destroy the Mafia’s power and popularity. Veering off behind it in every direction is a honeycomb of tiny little streets – so narrow that it would be pointless trying to squeeze through in any vehicle larger than a three-wheeler – each with lines of washing hanging all along them. Sicily has not traditionally been a rich place and the modest homes in Palermo partly explain why the city isn’t like any other. It’s like a house with lots of different rooms, and the streets are the room that everybody shares.

Hidden within these labyrinthine alleyways is one of the masterpieces of Baroque sculpture. Giacomo Serpotta spent 50 years in the 17th and 18th centuries completing the interior of the Oratorio del Rosario di Santa Zita, which looks at first like it might be made of marble, but is in fact a fine stucco mixed with marble dust. The whole church is covered with stories – scenes from the life of Christ and the Nativity – each one a window-box-sized stage and dense with figures. Serpotta covered everything with cherubim putti – decorative babies – which frame the scene but are not actually part of the story. They mimic what our response to the story might be. So when Christ is crucified, the babies all around the ceiling are crying, and when Christ is a little baby himself, sleeping in the manger, one of the cherubs has his finger to his lips as if to say ‘Shush! You’ll wake him up.’

Serpotta was trained in the part of Palermo where they made floats for religious processions and carnivals, as well as props for the theatre. So although he became a specialist in religious art, his work still had a theatrical streak to it. His sculpture at the Santa Zita is a wonderful thing: hugely sophisticated in the level of its craftsmanship and yet entirely popular at the level of its appeal.

One of the things that I like about Sicilian art is that it was always very out of step with mainstream Italian art. Because the population was so poor – and, I think, because there was such a strong Spanish presence – art never became sophisticated in the Renaissance sense. The idea that art would somehow speak at a very high level, that senior clergymen and the Pope would understand but ordinary people wouldn’t, never really caught on in Sicily. Art was always for the people.

To participate in Sicily’s communal and genuinely popular approach to religion, there’s nowhere better than Modica on Easter Sunday. This southern town of higgledy-piggledy houses tumbling down a steep hillside is home to the Madonna Vasa Vasa – an enactment of the sorrow and the joy of the Christian story as a huge piece of public theatre. The idea that Modica exists under the protection of the Virgin Mary is ingrained into the very fabric of this place. Looming over its citizens from the town’s highest point is one of Sicily’s most extraordinary Baroque churches, the Chiesa di San Giorgio. Its façade looks very much like an image of Madonna, its curved shapes echoing that of a woman’s body. Like many other local buildings, it is made from a beautiful, honey-coloured stone – at sunset, the town turns as pink as a prawn.

On the morning of the Madonna Vasa Vasa on Easter Sunday, everyone dresses in their finest. The street becomes a catwalk, from three-piece 1960s suits that you might otherwise only see in a Fellini film to teenagers in coordinated colours. Two huge processions, one carrying the Virgin Mary and the other carrying Christ, make their way through the streets to music with a sombre drumbeat, each purposely evading the other. By midday, 30,000-odd people have congregated in the town square, as mother and child finally come face to face.

Mary – a sort of life-size puppet in this portrayal – opens her cloak to release a clutch of doves and the audience waits to see what happens next. If the birds fly skywards, it is taken as an augury of a good harvest. The climax of the ceremony is the vasa vasa (‘kiss kiss’). At the moment the statues are brought together in an embrace, it’s as if the local football team has just won the cup, the crowd erupting with cries and shouts of celebration.

The people gradually disperse home or to local restaurants to eat painted eggs, roasted lamb and pies crafted into elaborate shapes – holy doves or heavenly stars – continuing the theatricality of the parade itself.

The festival celebrates life after death, and in Sicily the contrast between light and dark, life and death, has always been extreme. Though the island, historically, is poor, things have always grown very well here. A drive along some of its long, straight, inland roads – like that from Modica to the hilltop town of Enna – passes huge tracts of unpopulated land, great wheat fields and wild, empty landscapes. From Enna, it is possible to look out in all directions across this vast, fertile island. It is not difficult to understand why so many different cultures wanted to own and occupy it.

The ruins of Selinunte, once one of the most powerful cities in the world, are one of the great legacies left by Sicily’s Ancient Greek colonisers. Sitting on a beautifully unspoiled stretch of coastline, the temples have shielded the area from the kind of overdevelopment that has ruined other parts of Sicily’s shore. The riverside area of land between Marinella di Selinunte and Porto Palo is a protected nature reserve, and from the beaches you can swim out to sea for a view of the ruins from the water or just sit and watch fishing boats bob by.

In 1998, the crew of one such boat, the Capitan Ciccio, was searching for prawns off Sicily’s southwest coast when it found an Ancient Greek bronze statue entangled in the net. Covered in barnacles and strings of seaweed, it emerged headfirst from the depths of the Mediterranean Sea. The boat’s captain, Francesco Adragna, tells me that it seemed ‘to dance out of the water’. The piece was worth at least £150 million at auction, but Francesco accepted just a tiny fraction of that sum from the local authority so that the statue might remain in Sicily. The Satiro Danzante, or Dancing Satyr, now has its own museum in the port town of Mazara del Vallo, where it was brought ashore. Undoubtedly one of the world’s great objects, the statue represents a character from classical mythology that accompanied Dionysus, the Greek god of wine, during his drunken rampages. Depicted in the middle of an ecstatic dance, the figure is full of movement, with startlingly white eyes that seem alive.

Sicily was just a satellite of Greece’s empire, but Mount Etna obviously had a huge impact on the Greek imagination, because it was the birthplace of so many of its myths. It’s where Persephone, daughter of Zeus, goes into the underworld; it’s where Zeus’s son Hephaestus (Vulcan is his Roman god equivalent) has his forge. Then there’s the myth about the cyclops Polyphemus. In Homer’s Odyssey, this one-eyed monster threw the top of a mountain into the sea to try to sink Odysseus’s ship – and when Etna explodes, a similar upheaval occurs. Etna is a ‘multi-flue’ volcano, which means that there’s no central crater, so an eruption can take place anywhere. This unusual geology is reflected in the texture of classical myth.

Today Etna is a strange and mysterious place, with dark black stone that looks like somebody’s just given the surface of the moon a going-over with a digger. Because the volcano is still active, the landscape is constantly changing. If you find a slope with the right degree of volcanic matter, you can take giant strides down the side of the mountain, Etna’s rubble shifting in small landslides under your feet. Although Etna is a world apart on Sicily, it encapsulates the island’s extremes. It’s created a desolate, post-apocalyptic landscape that seems like it’s all about death, but just a stone’s throw away is the most incredibly fertile volcanic soil, where everything from grapevines to tomatoes flourish and grow.

The article 'Sicily, an island of secrets' was published in partnership with Lonely Planet Magazine.