The Fortezza is the citadel of the city of Rethymno in Crete, Greece. It was built by the Venetians in the 16th century, and was captured by the Ottomans in 1646. By the early 20th century, many houses were built within the citadel. These were demolished after World War II, leaving only a few historic buildings within the Fortezza. Today, the citadel is in good condition and is open to the public.

The Cretan War, also known as the War of Candia or the Fifth Ottoman–Venetian War, was a conflict between the Republic of Venice and her allies against the Ottoman Empire and the Barbary States, because it was largely fought over the island of Crete, Venice's largest and richest overseas possession. The war lasted from 1645 to 1669 and was fought in Crete, especially in the city of Candia, and in numerous naval engagements and raids around the Aegean Sea, with Dalmatia providing a secondary theater of operations.