Discover Caetani Castle

Last updated on October 8, 2026

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Introduction

Sermoneta is a walled hill town in the province of Latina, and the castle is the mass at the top of it. It was built by the Annibaldi family and then bought and enlarged by the Caetani in the thirteenth century, which is the family it still carries the name of.

Architecture

The Castello Caetani is a building with one idea, pursued without compromise: that the defender should be able to keep giving ground. The outer walls are over three metres thick and the circuit rests on living rock rather than on foundations; inside it the Caetani built five further rings of walls. Each can be lost without losing the next.

The keep carries the logic to its conclusion. The maschio is not structurally part of the castle at all -- it stands independent, joined to the buildings around it only by two wooden drawbridges, so that raising them turns the tower into a separate fortress with the lord's bedchambers inside it. The expectation written into the design is explicit: if the whole complex fell, the staff and servants were to be inside the keep when it did.

What the Borgia added in the fifteenth century, under Alexander VI and by Antonio da Sangallo, was more fortification rather than a change of register -- Borgia Cittadella and the Casa del Cardinale. The softening comes later and in the interiors: the Sala dei Baroni and the Camere Pinte, where a fortress acquires painted rooms.

The short history

The Annibaldi built it, the Caetani bought it for 140,000 florins, and a Borgia pope simply took it.

Read the full historical timeline guide →

How it was built and evolved over time

The Annibaldi built a weapon, not a house. The castle went up at the beginning of the thirteenth century at the will of the Annibaldi family, and it was conceived as a military fortress at a strategic point of the territory between Rome and Naples rather than as a noble residence: outer walls over three metres thick, the whole protected by a circuit resting on living rock. Of that first construction only the keep and the counter-tower called the maschietto remain.

In 1297 it was bought for 140,000 gold florins. The Annibaldi sold the territories of Sermoneta, Bassiano and San Donato to Pietro Caetani, nephew of Pope Boniface VIII. The Caetani spared nothing in turning the Annibaldi rocca into a true military fortress, with new buildings and five rings of walls which, through a system of drawbridges, made it possible to isolate the tower under attack.

Then a Borgia pope confiscated it. Alexander VI excommunicated the Caetani immediately on his election in 1492, and in 1500 confiscated all their fiefs and entrusted them to his children Cesare and Lucrezia. He completed the castle with further fortification work by Antonio da Sangallo, including the Casa del Cardinale and Borgia Cittadella. Onorato Caetani had already survived an ambush perhaps laid by the Borgia -- an early signal of the danger the family was in.

The sixteenth century was its best. Under Onorato III Caetani, around the middle of the century, Sermoneta reached its greatest splendour; he was an energetic man and a born commander, as he showed at the battle of Lepanto.

Napoleon's men stripped it. The fortress was attacked many times over the centuries, and in 1798 it was sacked by Napoleon's soldiers, who turned it into a prison and carried off thirty-six cannon.

A Caetani put it back. The castle returned to the family towards the end of the nineteenth century with Gelasio Caetani, to whom the imposing restoration of the old family seat is owed. During the Anzio landing of 1944 it was still lived in by Roffredo and Marguerite Caetani, together with their tenants who had fled the Pontine plain. Since 1977 it has belonged to the Fondazione Roffredo Caetani, created by the last descendant of the Caetani of Sermoneta, Lelia Caetani, who died on 11 January of that year.

Frequently asked questions

Can I visit without booking?

Generally no. Entry to the Castello Caetani is by guided visit only, on published days and in timed slots, with the entry contribution bought in advance through the Giardino di Ninfa shop. The exception is a disabled visitor with a companion, who may buy at the castle without booking a slot.

What does it cost?

8 euro a person for an individual, plus 0.25 euro online presale; 6 euro a person for a disabled visitor with a companion; free for children under 12 accompanied by a parent.

When is it closed?

Mondays, the weekly closing day. The castle itself closes an hour after the ticket office.

Did Lucrezia Borgia really live here?

She stayed at Sermoneta for periods during the pontificate of her father Alexander VI, who had confiscated the Caetani fiefs in 1500 and entrusted them to her and to Cesare.

What survives of the original castle?

Only the keep and the smaller counter-tower called the maschietto. Everything else is Caetani or Borgia work on top of the Annibaldi fortress of the early thirteenth century.

Who owns it?

The Fondazione Roffredo Caetani, since 1977. It was created by Lelia Caetani, the last descendant of the Caetani of Sermoneta, who died on 11 January 1977.

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Sources & verification Covers the sourced claims on this page.

Checked against Wikipedia — The castle was built at the will of the Annibaldi family at the beginning of the thirteenth century, conceived more as a military fortress at a strategic point of the territory between Rome and Naples than as a noble residence: the external walls are over three metres thick and the whole structure is protected by a circuit of walls resting on living rock, and of this first construction only the keep and a counter-tower called the maschietto remain, The main nucleus of the Castello Caetani is the keep, which housed the lord's bedchambers and served as the last refuge in case of enemy invasion; the structure of the keep was completely independent of the rest of the castle and was connected to the adjacent structures only by two wooden drawbridges that could be raised when needed, and the staff and servants would take refuge inside it should the whole complex fall into enemy hands. Near the keep rises the second, much smaller tower called the maschietto, and outside the two towers is the great parade ground, An important signal of the danger to the Caetani family was the ambush of which Onorato himself was the victim, perhaps laid by the Borgia; as soon as Alexander VI Borgia was elected pope in 1492 he immediately excommunicated the Caetani and in 1500 confiscated all their fiefs, entrusting them to his children Cesare and Lucrezia Borgia. Alexander VI completed the manor with further fortification works by Antonio da Sangallo, which also included the construction of the Cittadella and the so-called Casa del Cardinale, Some buildings of the Castello Caetani were partly demolished by the Caetani, who created the Sala dei Baroni, modified by the Borgia in the fifteenth century, and the rooms called the Camere Pinte, restructured at the end of the 1990s; this last group consists of three guest rooms, two of which are frescoed by an unknown author attributed to the school of Pinturicchio with images representing mythological figures and the theological virtues (October 2026).