During the 6th century, the centre of the city was transferred at the heart of the lake Orestiada by Justinian I, who also built a fortification with double walls – few remains have survived to this day. In the meantime, the following erection of Byzantine churches as well as the often emperor’s visits are justifying the value of Kastoria for the Byzantine Empire.
The city of Kastoria itself has existed since 840 B.C., by that time Argos Orestiko was the kingdom of Ancient Orestiada, (aka Macedonia, the later the dominant state of Hellenistic Greece). From 359 B.C., Ancient Orestiada joined the Kingdom of Macedonia and Orestians teamed with the Macedonian phalanx. In the wake of the Roman occupation, 197 B.C., Kastoria was named “Keletron”, as stated by Titus Livius (Roman historian, 64 B.C.-17 A.D.).
From the 10th century to the 14th century, Kastoria passed to a series of conquerors: Bulgarians (927-969-990 A.D.), Byzantines (1019-1083), Normans (throughout 1082), the Despotate of Epirus (1252-1315) and Serbs (1331-1345).
In 1383, Kastoria was ruled by the Turks and for the duration of the Ottoman Empire (527 years), the city enjoyed many privileges that stimulated independence and freedom of movement for the fur crafters residing there. Being privileged, Kastoria consequently became a great center of Hellenistic culture, preserving the national awareness and Greek language, and thus grew intensive economic and commercial activity. Following the erection of Byzantine churches by the emperors in the past, the aristocratic class now, continued to build even more temples.
Right after the Greek War of Independence (1821) and the liberation of many counties from the Turkish rule, Kastoria welcomed the new formed "Filiki Eteria" (or Society of Friends, 1867), which started the uprising of Macedonia against the Ottomans. Through the period of the Macedonian Struggle (1904-1908), the whole region was the center of the battles between the Greeks against the Bulgarian Komitadjis (who were acting against the Ottoman Empire, but for their own benefit).
Kastoria was finally liberated during the 1st Balkan War (November 11, 1912), on the same date of the nameday of Agios Minas, who since has been celebrated as the liberator and patron Saint of the city.
Subsequent to the Asia Minor Catastrophe and the compulsory exchange in the Greek -Turkish populace in 1923 (the Treaty of Lausanne), the city of Kastoria along with the wider region, received a large number of refugees who accordingly vivified economically and spiritually the life of the whole county.
At the beginning of the World War II (1940), the city was attacked by Italian bombers and as a result, the entire Jewish community of Kastoria was violently transferred to the concentration camps (March 24, 1944).
Straight after the Greek Civil War (1946-1949) became a national "wound", given that Grammos mountain range and Mount Vitsi were turned into the war zone of the Democratic Army of Greece and the Greek Army, which ultimately led to such a tragic consequences (hunger, poverty and sicknesses).
During the ‘50s, once again Kastoria experienced economic flourish and became one of the world's major production, processing and trade fur center. Particularly in the ‘70s, Kastorians touched the very top places on the lists of the top GDP-per-capita countries. By that time, more than 5,000 small and large fur businesses were operating in the city, occupying about 15,000 workers.
At present, the universal economic crisis brought a decline to fur trade - that lead to a great migration crisis, so Kastoria is still is counting its wounds - except the fact that the city continues to be the only fur processing center in Europe.