Inhabitation is attested from 9000 BC.
During the period of Ottoman rule in Thessaly, the main settlement in the location of modern Karditsa was called Sotira.
In 1810, the English traveler William Martin Leake mentioned a sprawling village named Kardhítza, consisting of between 500-600 houses, of which the majority of the inhabitants were Turkish.
Karditsa was incorporated as a new city in 1882, the year after its liberation from the Ottoman Empire.
During World War II, the resistance in Thessaly was fought primarily by the ELAS.
In March 12, 1943 Karditsa was the first city in Europe to be liberated from Nazi occupation in the campaign fought by the ELAS.
Source: wikipedia.org