On the wilder Lombard (western) shore of Lake Garda, monolithic slabs of beige Botticino marble cluster atop a hill. From this circular mausoleum platform can be seen a very strange citadel. Below are cypress-studded garden terraces, an open-air theatre and a sprawling honey-stuccoed country pile with dark recesses. Metallic masts, foghorns and guns aboard the prow of First World War warship Puglia float in the tree canopy. Beyond this fantastical landscape, with its bombastic interventions and collections of art and artillery, the shimmering lake lies calm.
This is Il Vittoriale, the final home of Gabriele D'Annunzio, the daredevil "poet-soldier", philanderer and proto-Fascist who created this lakeside fantasy, inspiring Mussolini and many megalomaniacs since.
Last week Lucy Hughes-Hallett's biography of D'Annunzio, The Pike, won the Samuel Johnson Prize for Non-Fiction. Her book certainly opens up D'Annunzio's life to the English-speaking world, but no reading would be complete without a visit to his home, playground, museum and national monument to the cult of personality.
Born in Pescara in 1863, the precocious poet and self-publicist launched his career in Rome, stirring up the press by announcing his own fatal fall from a horse. A literary career and the first flirtations with decadence brought initial notoriety before debt forced D'Annunzio to flee to France in 1910 where he collaborated with Debussy and wooed the dames. French writer Romain Rolland dubbed him a predatory "pike" – "afloat and still, waiting for ideas". D'Annunzio got his kicks and inspiration from sex, death and superman deeds.
The First World War started and he returned to serve in the Italian army, navy and air force, losing the sight in one eye, stoking nationalism and leading audacious missions – including a flight over Vienna dropping propaganda leaflets and a torpedo boat raid.
In 1919, he led the occupation of Fiume (now Rijeka in Croatia) where he established the Regency of Carnaro, with himself – Il Duce (leader) – at the helm. Between 1922 and D'Annunzio's death in 1938, Mussolini and the Italian state funded the transformation of his lakeside home, Il Vittoriale degli Italiani: the Shrine of Italian Victories – mainly so that the troublesome and popular hero could be kept away from Rome and the new, shiny-scalped Il Duce demagogue.
A guided tour of Vittoriale begins under the Prioria (priory) façade, pockmarked with heraldic crests. Upon entering the mansion's gloomy rooms – photophobia made D'Annunzio avoid strong sunlight in his later years – a curator/guide briefs us. If you can read a man through his possessions and taste, then a look around Il Vittoriale leaves tangled clues of a libertine life. Some 10,000 books and 3,000 objects – many belonging to former resident of Villa Cargnacco and art historian Heinrich Thode – fill the place. D'Annunzio called it a "book of living stones".
In the entrance hall is a clue to his myth-making as the motto-loving poet and seducer. Guests are welcomed with a Latin inscription that boasts of his calling as a modern-day visionary: "I am Gabriel who stands before the gods, among the winged brothers uniquely sighted."
Each of D'Annunzio's rooms has specific function and hierarchy. Each space presents an array of symbols and artefacts carefully selected and placed. There are two waiting rooms – one for welcome guests, the other for formal visitors called the Mask Wearer's Room. Mussolini, a regular visitor, was shown the latter in 1925. The gramophone and radio here may have kept him amused.
Amid the religious iconography of the Relic Room is the broken steering wheel from the boat in which Sir Henry Segrave was killed while attempting the world water speed record. An inscription edits out lust and greed from the Seven Deadly Sins: "As there are five fingers on a hand, there are only five mortal sins." The series of bedrooms and bathrooms hosted D'Annunzio's many lovers, while a cradle/coffin-shaped bed in the Leper's Room was where D'Annunzio's body was laid in 1938.
Elsewhere in the grounds the Secret Museum displays clothes, shoes and jewellery – much of it designed by D'Annunzio for himself and his female friends, including the actress Eleonora Duse. Dressing as a dandy aesthete, he produced reams of journalism, poetry, prose and theatre. A nightgown with a boastful aperture and a pair of leather slippers stitched with phalluses make for comic relief after the Art Deco finery of Schifamondo (meaning "Escape from the World") designed by architect Maroni but never inhabited by D'Annunzio. The transatlantic liner decor here backdrops war museum documents, uniforms and the fragile-looking aircraft flown over Vienna.
Like the Futurists, D'Annunzio embraced the speed of modern technology, communications, cinema and transport: cars, planes and weaponry appear all over Il Vittoriale. The warship Puglia, a gift from the navy in the 1920s, juts into the hillside of Gardone Riviera. Below the ship's decks, that hosted D'Annunzio's parties, is a naval museum, while on the hill a mausoleum holds his remains and those of friends.
Lucy Hughes-Hallett describes D'Annunzio's relationship with the place: "Immured in his gorgeous refuge, he likens h imself to Napoleon on St Helena, to Bluebeard in his castle, to Nero the artist-tyrant, or to an ancient king, entombed with his treasure 'according to ancient rites'."
"The Pike" has struck again, still grabbing attention 150 years since his birth – and a visit to Il Vittoriale fascinates and unsettles.
'The Pike: Gabriele D'Annunzio: Poet, Seducer & Preacher of War,' by Lucy Hughes-Hallett, is published by Fourth Estate, £25
British Airways (0844 493 0787; ba.com) and easyJet (0843 104 5000; easyjet.com) both fly to Verona from Gatwick, Monarch flies from Manchester and Jet2 flies from Manchester and, as of May next year, from Edinburgh.
Grand Hotel Gardone reopens in April next year (00 39 0 365 20261; grandhotelgardone.it). Doubles from €235 (£196), room only.
The Tower of the Old King B&B (00 39 338 7063578; thetoweroftheoldking.it) has doubles from €85 (£71), including breakfast.
Il Vittoriale (00 39 0365 296511; vittoriale.it) is open year round, from 8.30am to 7pm in summer, and 9am to 4pm in winter. Tickets cost €8-€16 (£6.60-£13.20).