Curious facts about Monte Porzio Catone that few people know

Monte Porzio Catone has fewer than nine thousand inhabitants, but popes, scientists, writers and a mysterious book that nobody can read have all passed through this hill. These are the stories we tell our guests when they ask “so what is there to see here?”.

The calendar started here

According to tradition, in 1582 Pope Gregory XIII issued the bull that reformed the calendar at Villa Mondragone. To bring the seasons back into line, 4 October 1582 was followed directly by the 15th: ten days vanished by law. The full story is in Villa Mondragone and the Gregorian calendar.

The book nobody can read

In 1912 the antiquarian bookseller Wilfrid Voynich bought around thirty old manuscripts from the Jesuits of Villa Mondragone. One was an illustrated volume with unknown plants, astronomical figures and a script that looks like no known language. Today it is called the Voynich manuscript, it is kept at Yale University and it is one of the great puzzles in the history of the book: linguists and code breakers have been trying for more than a century. More in the Voynich manuscript and Villa Mondragone.

Galileo and Marconi in the same villa

Villa Mondragone also has a scientific history. According to the European Physical Society, in 1611 Galileo Galilei showed the discoveries he had made with his telescope there, and in 1932 Guglielmo Marconi carried out microwave experiments there. In 2025 the villa was recognised as a historic site of European physics. Since 2010 a Foucault pendulum has swung in the library, which the FAI describes as the tallest in central Italy.

Stars above a Roman villa

The Rome Astronomical Observatory, whose building was designed at the end of the 1930s and assigned to the institute in 1948, stands above the remains of the Roman villa of Matidia, a relative of the emperor Hadrian. People study galaxies and cosmology where two thousand years ago others went on holiday.

A hermitage only men may enter

On the hills above the town, at about 550 metres, is the Tusculan Hermitage of the Camaldolese monks, founded in 1607 and finished in 1613, dedicated to Saint Romuald. The hermitage is still lived in by monks and is the mother house of their order: only men may go inside. At the door you can buy honey, oil and wine made by the monks.

The Barco was a hunting enclosure

The name of the Barco Borghese has nothing to do with boats (barca in Italian). “Barco” meant an enclosure for game: the Borghese princes used the huge Roman terrace as a hunting reserve.

George Sand wrote a novel about it

In 1858 the French writer George Sand stayed at Villa Mondragone and used it as the setting for her novel La Daniella. Pauline Bonaparte, Napoleon’s sister and wife of Camillo Borghese, had her summer residence at nearby Villa Parisi.

The name written as one word

The town is called Monte Porzio Catone, as three separate words. Yet for years the motorway sign read “Monteporziocatone”, all run together, until in 2022 it was corrected after complaints from residents. Why “Catone” and why “Porzio” is explained in why is it called Monte Porzio Catone.

A wine museum in a railway station

Trains have not stopped at Monte Porzio since 1944. The old station of the Rome to Fiuggi line now houses the Wine Museum, opened in 2024, which tells the story of the vineyards and cellars of the Castelli.

Orchids, nativity scenes and Sant’Antonino

The town’s year has a few fixed events: in April the Orchidee dal Mondo orchid show in the old town, on 2 September the feast of Sant’Antonino Martire, the patron saint, and around Christmas the international nativity scene exhibition. Dates and programmes change every year and are published on the town council’s website. The full calendar is in festivals and traditions.

In short

• 1582: the Gregorian calendar, from Villa Mondragone.
• 1611 and 1932: Galileo and Marconi in the same villa.
• 1912: the Voynich manuscript leaves Mondragone.
• Tusculan Hermitage: founded in 1607, men only.
• Barco: a hunting enclosure, not a boat.
• Read next: the history of the town, Tusculum.