The castle was built between 1220 and 1223, during the rule of the
Prince of Achaea Geoffrey I of Villehardouin, as a result of a dispute between the Prince and the clergy of the Principality. Geoffrey had asked the clergy, which owned almost a third of the Principality's lands but was not obliged to render military service, for additional donations to help defend the realm. When the clergy refused, claiming that they owed allegiance only to the Pope, Geoffrey confiscated Church property, and began construction of Chlemoutsi with the new funds. The fortress was set on a new foundation, with no previous structure identifiable on this site. Its French name,
Clairmont or
Clermont, most probably gave rise to the Greek form of
Chlo[u]moutsi, which more recently became
Chlemoutsi, although various theories have been proposed as to the name's origin, with suggestions of Greek, Albanian or Slavic roots pre-dating the Frankish fortress. From the 15th century, Italian sources came to call it
Castel Tornese, apparently through a confusion with the seat of the Principality's mint in nearby
Glarentza, which until the middle of the 14th century minted silver
tornese coins. The new fortress was near the princely capital of
Andravida, some away, and ca. from the Principality's largest port and town, Glarentza. These three sites were the administrative heart of the Principality and, along with the fortress of
Beauvoir or Pontiko at
Katakolo further south, served to secure control of the fertile plain of
Elis, which formed a major part of the princely domain (along with
Corinthia and the
Evrotas Valley in
Laconia). Despite its importance, however, throughout the history of the Principality of Achaea Chlemoutsi was never the object of major military operations; rather, its main function seems to have been as a prison for distinguished captives, such as the Byzantine generals taken captive at the
Battle of Makryplagi in c. 1263, one of whom,
Alexios Philes, died in captivity there. with its principal locations during the late Middle Ages. Chlemoutsi is located on the westernmost promontory of the peninsula. of the west coast of the Peloponnese from 1867. Chlemoutsi is located near the top. When the Prince
William II of Villehardouin died in 1278, the princely domain, as well as the princely title, went to the
King of Naples,
Charles of Anjou, according to the provisions of the
Treaty of Viterbo. Chlemoutsi, however, had been granted by William to his wife,
Anna Komnene Doukaina, who retained it, along with the Villehardouins' hereditary
Barony of Kalamata in
Messenia. In 1280, Anna married the baron
Nicholas II of Saint Omer, lord of one half of
Thebes. The latter's acquisition of some of the "most fertile lands and the most powerful fortress in the
Morea", in the words of the French medievalist
Antoine Bon, in addition to the wealth he had inherited from his first marriage, worried King Charles. On 25 September 1281, an agreement was reached whereby Chlemoutsi and Kalamata were ceded to the princely domain in exchange for half the lands of the recently deceased
Leonard of Veroli, comprising estates in both the Morea (in Elis and Messenia) and
Italy. In the early 1290s,
Thomas Komnenos Doukas, son and successor of the
Despot of Epirus Nikephoros I Komnenos Doukas, was held at Chlemoutsi as a hostage for his father's behaviour. In c. 1311, the sole surviving daughter of William II Villehardouin,
Margaret, sought, by virtue of her descent, to claim the Principality, or at least a portion of it, including Chlemoutsi and Kalamata, from the
Angevin Kings of Naples who had controlled it since 1278. To this end, in February 1314, she wedded her only daughter,
Isabel of Sabran, to
Ferdinand of Majorca and passed her titles and claims to them. She then returned to Achaea, where she was imprisoned by the Angevin
bailli at Chlemoutsi, where she died in February or March 1315. Ferdinand landed at Glarentza in June 1315, claiming the Principality from the Angevin nominee,
Louis of Burgundy. Chlemoutsi and most of Elis fell rapidly under Ferdinand's control, but he was eventually defeated and killed in the
Battle of Manolada in July 1316. The remaining Majorcan troops ceded the fortresses they held in Elis and set sail for home shortly after. In 1418, Glarentza and Chlemoutsi passed into the hands of
Carlo I Tocco, who began to expand his territories in the Morea at the expense of Prince
Centurione II Zaccaria. After his defeat by the
Byzantine navy in the 1427
Battle of the Echinades, however, Tocco was forced to cede his possessions to the
Despot of the Morea,
Constantine Palaiologos (who would become the last
Byzantine emperor), in the form of a dowry for his daughter
Maddalena Tocco. Chlemoutsi now became Constantine's residence and his base of operations against the last major Latin stronghold, the city of
Patras, in 1428–30. The castle remained in Byzantine hands until it was captured, along with the rest of the Morea, by the
Ottoman Empire in 1460. The bastard son of Centurione II,
John Asen Zaccaria, was also imprisoned at Chlemoutsi, but managed to escape in 1453 and lead a
rebellion against the Byzantine Despots of the Morea. With the Ottoman conquest, the castle lost much of its strategic significance. However, it was occupied by the
Venetians during the
Ottoman–Venetian War of 1463–79, and attacked by the
Knights of Malta in 1620. During the period of
Venetian rule in the Peloponnese (1687–1715) after the
Morean War, it served as the seat of a fiscal district. Moreover, the reports of the Venetian governors at the time dismiss Chlemoutsi as small in size and barely inhabited. In 1701 the
provveditore generale Francesco Grimani proposed that it be destroyed, as it was too far from the sea—a vital concern for the maritime-minded Republic—and difficult to defend, and recommended that Glarentza, by then abandoned and ruined, be rebuilt instead. In 1715, the Morea
returned to Ottoman control, and by the early 19th century, the fortress had been completely deserted. In 1821,
Konstantinos Andravidiotis defeated the Ottoman forces in
Elis, after which they retreated inside Chlemoutsi. Thus begun the unsuccessful
Siege of Chlemoutsi under
Georgios Sisinis and
Charalambos Vilaetis, which was lifted after Ottoman forces from Lalas counterattacked. In 1825, the forces of
Ibrahim Pasha of Egypt took the castle and dismantled a portion of its walls so that it could not be used by the Greek rebels. Today the castle is a preserved landmark under the 6th
Ephorate of Byzantine Antiquities. It can be visited and is easily accessible by car from nearby Kyllini. ==Location and architecture==