Catania is black with lava stone and full of beautiful contradictions. Castello Ursino – commissioned by Frederick II of Swabia in the 13th century – is its perfect symbol: sober, imposing, built to last. Consider that it originally stood by the sea, then Etna decided otherwise and today it sits wedged between the buildings of the city centre.

Inside is the Civic Museum, with a collection of medieval and modern art that surprises every time. Allow at least a couple of hours, without rushing.

Castello Maniace is one of those places that takes your breath away the moment you see it, positioned as it is at the very tip of Ortigia, with the sea wrapping around three of its sides. This too is by Frederick II, this too is from the 13th century – but its position makes it unique across the entire island.

The name comes from George Maniakes, the Byzantine general who in the 11th century wrested Syracuse from the Arabs. The Gothic-Swabian marble portal at the entrance is one of the most beautiful things you will see on this journey.

Donnafugata is not a medieval castle in the strict sense – it is a Neo-Gothic villa from the 19th century, the property of the Arezzo de Spuches barons. But it has everything one asks of a castle: 122 rooms, a park with mazes and artificial grottoes, an atmosphere suspended between the romantic and the unsettling.

If the name sounds familiar, it’s because several scenes of Inspector Montalbano were filmed here. Coming after watching the series is a strange and beautiful experience.

Enna is the highest provincial capital in Italy – nearly 1,000 metres – and the Castello di Lombardia has watched over it from above since before the year 1000. Its origins are Siculian, the current structure Norman and expanded by Frederick II. Of the original twenty towers, six remain, including the Torre Pisana, from which on a clear day you can see the whole of Sicily.

Bring a jumper even in summer – there is always wind up there, and the view from the Torre Pisana is worth any thermal discomfort.

This is my favourite. The Castello di Mussomeli – also known as Manfredonico after the Chiaramonte family who commissioned it – rises on an isolated rocky crag at 778 metres altitude. Seen from the motorway it looks suspended in mid-air. Up close it is even more impressive: the walls follow the rock, as though they grew out of it.

It is not an easy castle to reach – the final stretch of road is narrow and at times awkward – but nobody who has been there has ever regretted it.

The Castello di Caccamo is among the best preserved in all of Sicily. Built by the Normans in the 12th century and later expanded by the Chiaramonte and De Spuches families, it dominates the valley of the San Leonardo river from a position that looks chosen by a painter. The village below is one of those places where time seems to slow down.

Inside there is everything: frescoed halls, an underground prison that sends shivers down the spine, furnished noble apartments. It is a living museum of Sicilian medieval life.

The Castello La Grua Talamanca of Carini is famous for a tragic story that every Sicilian knows: the murder of the Baroness Laura Lanza, killed for reasons of honour in 1563. She was a young woman in love with her cousin, and her husband did not forgive her. The story became an anonymous poem, one of the most beautiful texts in Sicilian literature.

On moonlit nights, they say, her lament can still be heard between the walls. I have never been there at night, but after reading the Baroness poem, the stones of the castle carry a different weight.

Erice is another world. At 750 metres above sea level, often wrapped in fog even in summer, with its medieval alleyways of white stone and that silence you don’t expect. The Castello di Venere – Norman, 12th century – was built on the ruins of a temple dedicated to the goddess of love, a pilgrimage destination from across the ancient Mediterranean.

From here you can see the entire western coast of Sicily, the Egadi Islands, the plain of Trapani, and on clear days even Tunisia. It is worth every hairpin bend of the cable car ascent.

The castle of Castellammare del Golfo is one of those places that works perfectly within its landscape – it looks directly out to sea, at the centre of the marina, and seems made to stand exactly there. Arab origins from the 9th century, then expanded by Normans and Swabians. It has been everything: military outpost, route control, symbol of the town.

Today it houses the Museum of the Sea and the surrounding area is the most beautiful seafront promenade in the province of Trapani. Stay for dinner.

We close with the most melancholic stop on the tour. The Castello di Calatubo can be seen from the A29 motorway, on that rocky crag that looks like an apparition. Many mistake it for an old monastery or a farmhouse. Few stop. It is in a state of abandonment, and that is precisely what makes it so moving: those walls have resisted for centuries despite everything, waiting for someone to take care of them.

Below lie Hellenistic remains and an ancient necropolis. The history of this place goes much further back than it appears.