The earliest evidence of habitation in the city of Rethymno comes from the late Minoan period (1550-1250 BC). It is much later on, though, that the city of Rithymna reaches its peak – namely in the 4th-3rd centuries BC.
With the exception of the Roman period, the city thereafter is in decline, making no mark on history. For the time of the First Byzantine era and the Arab rule, historical information is scanty indeed.
Everything changes from 1211, with the acquisition of Crete by the Venetians, who appreciated the importance of the harbour here. Right away they established the Castel Vecchio – a small fortified core to the settlement: this soon expands and receives new defences. This Venetian work runs from the seashore at the east to that on the west, but left the city wide open from the sea itself. As a result, in 1571 the Algerian pirate Ulu Ali managed to destroy and plunder the city without meeting any serious resistance. The Venetian response was to construct the Fortezza on Palaiokastro Hill: the largest military undertaking yet seen on Crete by them, it took 15 years to complete (1573-1588).
The start of the 16th century was a boom time in the city. The Cretan Renaissance (16th-17th centuries) sees a blossoming in Literature and Art.
It is period written about by Marino Zane Bounialis (The Cretan War), a lengthy poem that chronicles the war between the Venetians and the Turks for Crete (1645-69): this gives many details about society in Rethymnon in the last days of Venetian rule. Other important intellectual personages of this era are Marcos Mousouros, Nikolaos Vlastos, Georgios Chortatsis (Erofili) etc.
With the conquest of Crete by the Turks in 1669 a time of cultural and economic decline begins at Rethymnon, which was largely abandoned by its inhabitants. During the years of the Independent State of Crete (1897-1913), Rethymnon province was under the care of the Russian and Polish troops, who departed for good in 1907. At this time some major development projects were undertaken, such as the building of bridges and roads.
In more modern times, Rethymnon was bombed in WW II and many houses destroyed. Basically the economic upturn for the city started in the 1970s – hand in hand with the development of tourism. A significant spur was given too by the installation of the Department of Pure Science - University of Crete at Galos (the other campus of the University of Crete).
Today it is an important tourist attraction for people from all over the world, particularly in the summer.