Castle of Acquafredda

A medieval fortress on an ancient volcano, setting of the legend of Count Ugolino

Near Siliqua, on a volcanic cone overlooking the Cixerri valley, the ruins of Castle of Acquafredda rise at an altitude of 256 metres: one of the most striking medieval landmarks in Sardinia.

Il colle, nato dal raffreddamento rapido di un domo andesitico oltre 27 milioni di anni fa, è oggi monumento naturale e custodisce una fortezza che fu teatro di vicende storiche.

From the Pisans to Count Ugolino

The castle, located within the Curatoria of Sigerro, already existed by 1215, but its importance grew when it became the property of the famous Pisan nobleman Ugolino della Gherardesca, Count of Donoratico. From 1257, after the fall of the Judicate of Cagliari, the count controlled from here the access route to wealthy Iglesias, whose silver, zinc, and lead mines brought immense wealth to Pisa.

After falling from power and being accused of treason, Ugolino was imprisoned in the Tower of Hunger in Pisa, where he died between 1288 and 1289 together with his sons and grandsons. His tragic end is told in Canto XXXIII of Dante’s Inferno: “La bocca sollevò dal fiero pasto / quel peccator, forbendola a’ capelli / del capo ch’elli avea di retro guasto” ("He raised his mouth from his atrocious meal / that sinner, and wiped it on the hair / of the very head he had been ravaging"), verses that still feed the mystery surrounding his story.

Dopo i Pisani, il castello passò agli Aragonesi dal 1326 al 1410, per poi essere progressivamente abbandonato e affidato a diverse famiglie feudatarie fino al riscatto da parte di Vittorio Amedeo nel 1785.

Three lines of defence

Il castello si articola su tre livelli difensivi che seguono l’andamento del colle, rendendo l’approccio nemico estremamente difficoltoso.

The keep,at the highest point of the site at 256 metres, was the fortified core where the castellan lived. Originally built on two floors with an upper terrace and an underground cistern, it still preserves imposing walls around 20 metres high, crowned with Guelph battlements. Five coats of arms remain on the northern wall, including the imperial eagle of the Gherardesca family. Opposite stands the Watchtower, at 248 metres, known locally in Siliqua as torre de s’impicadroxiu. According to tradition, this is where Vanni Gubetta, one of Ugolino’s betrayers, was imprisoned.

Halfway up the slope, at 200 metres, stands the powerful Cistern Tower, an isolated quadrangular structure with three connected rooms, now accessible thanks to an internal staircase. Water was essential for the castle’s survival during sieges.

At the base, at 154 metres, the third defensive line enclosed the village area, with soldiers’ quarters, warehouses, and the probable Church of Santa Barbara, identified in 2005, where three human burials were found.

A natural monument

Since 1993, the Andesitic Dome of Acquafredda has been designated a Natural Monument. The hill can be seen from every direction across the surrounding plain, while from the top it offers breathtaking views over the Cixerri valley, the wetlands of Cagliari, the sea, the Marmilla region and, on clear days, the Gennargentu massif.

La vegetazione, che accompagna l’intero percorso di visita, è costituita da una tipica macchia mediterranea con ginepro, lentisco, olivastri secolari ed euforbia. Alla base, un rimboschimento di pini ospita un’area picnic e un sentiero natura con attrezzi ginnici.

The local fauna includes rare species such as the lesser kestrel, an indicator of an unspoilt habitat, as well as buzzards, kestrels, ravens, Sardinian partridges and, occasionally, large birds of prey from nearby Monte Arcosu.

Visitor information

Location: Siliqua, 4 km from the village centre, along the SS 130, about 30 km from Cagliari.

Opening hours and bookings: Guided tours are available by reservation. The route includes information panels and an audio guide that can be downloaded to your smartphone in Italian, English, French, German, and Spanish. For prices, opening times, exhibitions, and events, please visit castellodiacquafredda.com