The Fortezza (fortress) is the citadel of the city of Rethymno in Crete. It is built on a hill which was the site of ancient Rhithymna's acropolis. Between the 10th and 13th centuries, the Byzantines established a fortified settlement to the east of the hill. It was called Castrum Rethemi, and it had square towers and two gates. The fortifications were repaired in the beginning of the 13th century.
Following the fall of Cyprus to the Ottomans in 1571, Crete became the largest remaining Venetian overseas possession. Since Rethymno had been sacked, it was decided that new fortifications needed to be built to protect the city and its harbour. The new fortress, which was built on the Paleokastro hill, was designed by the military engineer Sforza Pallavicini according to the Italian bastioned system.
Construction began on 13 September 1573, and it was complete by 1580. Although the original plan had been to demolish the old fortifications of Rethymno and move the inhabitants into the Fortezza, it was too small to house the entire city. The walls along the landward approach to the city were left intact, and the Fortezza became a citadel housing the Venetian administration of the city. It was only to be used by the inhabitants of the city in the case of an Ottoman invasion.
On 29 September 1646, during the Fifth Ottoman–Venetian War, an Ottoman force besieged Rethymno, and the city's population took refuge in the Fortezza. Conditions within the citadel deteriorated, due to disease and a lack of food and ammunition. The Venetians surrendered under favourable terms on 13 November.
The Ottomans did not make any major changes to the Fortezza, except the construction of a ravelin outside the main gate. They also built some houses for the garrison and the city's administration, and they converted the cathedral into a mosque. The fort remained in use until the early 20th century.
Large-scale restoration work has been under way since the early 1990s. The Fortezza is managed by the Ministry of Culture and Sports, and it is open to the public. The Ottoman ravelin now houses the Archaeological Museum of Rethymno.
References:Château de Niort is a medieval castle in the French town of Niort. It consists of two square towers, linked by a 15th-century building and dominates the Sèvre Niortaise valley.
The two donjons are the only remaining part of the castle. The castle was started by Henry II Plantagenet in the 12th century and completed by Richard the Lionheart. It was defended by a rectangular curtain wall and was damaged during the Wars of Religion. In the 18th century, the castle served as a prison.
The present keeps were the central point of a massive fortress. The southern keep is 28m tall, reinforced with turrets. The northern tower is slightly shorter at 23m. Both are flanked with circular turrets at the corners as well as semicircular buttresses. Each of the towers has a spiral staircase serving the upper floors. The Romanesque architecture is of a high quality with the dressed stones closely jointed.