The Venetian fortress of Fortezza is built of the hill of Paleokastro, west of the modern city. The ancient city of Rithymna and the temple of Artemis were also located on this hill.
The engravings found in various parts of the hill suggest the existence of an acropolis. The settlement was possibly near the harbour. However, we have no information about the form of the settlement or the form of the acropolis and the temple. In the following centuries, the city of Rethymno was built at the same site. The Castel Vecchio, the small fortified settlement of the Byzantine times, was preserved until the middle of the 16th century. In 1540, the construction of a new fortification wall began, which would also protect the peasants’ settlement that extended beyond the Castel Vecchio. However, the raid of the Ottomans in 1571 and the destruction of the city necessitated new fortification works.
In 1573, the Fortezza was built on the hill of Paleokastro. Its original target was to include all the houses of the city, which was not achieved in the end. The inhabitants of the city started rebuilding their houses after the Ottoman danger was removed. The works in the area of Fortezza were completed in around 1580. Inside the castle only the Venetian guard was housed, as there was too little room left for private houses to be built, after the public buildings had been completed. The area in which the castle was built was small anyway. This affected the general organization of the fortress. The rocky soil, the lack of a ditch and the small open area in front of the fortress (spianata) meant that Fortezza was weak. Even the system of the four bastions was not complete, as it did not include the necessary elements of a complete bastion. However, some of its weaknesses were outbalanced by the well-studied organization of the interior. Near the enclosure there were no buildings and the southern side, which was the most vulnerable to attacks, was protected by “cavalieri”. The ammunition storerooms were on the western side and the buildings that were necessary during a siege were on the southern side.
After 1646 and the conquest of the city by the Ottomans, the Fortezza underwent significant changes. Additions and improvements were made to it. The number of houses built inside the castle was increased. In the beginning of the 20th century the area inside Fortezza was almost completely covered with buildings. Gradually, the houses were removed outside the castle and the Municipality of Rethymno demolished the ruined buildings. In the meantime, these plots were expropriated by the Municipality, the Archaeological Authority and the Tourism Organization. Today the fortress of Fortezza is the most important monument of Rethymno, the trademark of the city. In its restored buildings cultural events and exhibitions are hosted, while the bastion of Prophitis Ilias houses the small Municipal Theatre “Erofili”.