There’s been a fortress at San Leo since the Romans founded a city on the rock. Later colonizers added to it until the fifteenth century, when Federico da Montefeltro realized that it was no match for the new gunpowder-charged weapons, and set his military architect, Francesco di Giorgio Martini, the task of creating a new one. The walls were built on a slight inward slope and backed with earth, thus reducing the impact of cannonballs. Three large squares were incorporated for the manoeuvring of heavy cannons, and every point was defended with firing posts.
From the eighteenth century San Leo was used as a prison for enemies of the Vatican, of whom the most notorious was the womanizing Count of Cagliostro, a self-proclaimed alchemist, miracle doctor and necromancer. At first the charismatic heretic was incarcerated in a regular prison, but on the insistence of his guards, who were terrified of his diabolic powers, he was moved to the so-called Pozzetto di Cagliostro (Cagliostro’s Well), now the fortress’s most memorable sight. The only entrance was through a trap door in the ceiling, so that food could be lowered to him without the warden running the risk of engaging Cagliostro’s evil eye. There was one window, triple-barred and placed so that the prisoner couldn’t avoid seeing San Leo’s twin churches. Not that this had any effect – Cagliostro died of an apoplectic attack, unrepentant after four years of being virtually buried alive.
As well as the fortress, there’s the pleasant old village to explore. St Leo arrived in the third century and converted the local population to Christianity, and the two village churches, though they failed to impress Cagliostro, are worth a visit. The Pieve was built in the ninth century, with material salvaged from a Roman temple to Jupiter, by Byzantine-influenced architects from Ravenna. Sunk into the ground behind the church is a sixth-century chapel founded by and later dedicated to St Leo, whose body lay here until 1014 when Henry II, Emperor of Germany, calling in at the town on his way home from defeating the Greeks and Saracens in Rome, decided to remove it to Germany. His plans were thwarted by the horses bearing the saint’s body – after a short distance they refused to go any further, so St Leo’s body was left in the small village of Voghenza near Ferrara. The heavy lid of the sarcophagus remains in San Leo’s twelfth-century Duomo, dedicated to the saint.