The Fortezza is built on a hill called Paleokastro (meaning “Old Castle”), 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 by Enrico Pescatore in the beginning of the 13th century. After Crete fell to the Republic of Venice, the settlement became known as the Castel Vecchio or Antico Castello, which both mean “old castle.”
Under Venetian rule, a small harbour was built in Rethymno, which became the third most important city on Crete after Heraklion and Chania. On 8 April 1540, a line of fortifications began to be built around the city. The walls were designed by the architect Michele Sanmicheli, and were completed in around 1570. These fortifications were not strong enough to withstand a large assault, and when Uluç Ali Reis attacked in 1571, the Ottomans captured and sacked the city.
