The town is known as Kesriye in Turkish,[12] Kostur (Cyrillic: Костур) in Bulgarian and Macedonian,[13] Kosturi in Albanian[14] and Kusturea in Aromanian.

Kastoria was the site of previous settlements, the first being Celetrum (or Keletron), a town located near a lake in Orestis and mentioned by historian Livy in reference to the events of 199 BC.

[6] In October 1083, emperor Alexios I Komnenos forced the garrison to surrender, recovering thus the town and convincing many Norman troops, including Peter Aliphas, to enter his services.

[24] Under the Bulgarians, Kastoria had a significant Romaniote Jewish community, with prominent individuals such as scholar Tobiah ben Eliezer.

[8] Following the conquest and depopulation of Constantinople, the Romaniote Jews from Kastoria were forcefully resettled by the Ottomans in Balat district as part of efforts to repopulate the city.

[31] The establishment of Ottoman rule resulted in the demise of the local Greek landowning class, and funding of the arts and culture in Kastoria was undertaken by its wealthy merchants.

When they were arrested by the Austrian authorities and handed over to the Ottomans, John Emmanuel admitted that he had smuggled a copy of Feraios' revolutionary song "Thourios" (Greek: Θούριος) into Kastoria and sang it there many times.

[35] Following the destruction of Moscopole (late eighteenth century), some Aromanian refugees attempted to settle in Kastoria, and their efforts were unsuccessful due to concerns by local Kastorians over economic competition from newcomers.

[39] Karavangelis thought that the post-Ottoman future of Macedonia would be decided by Balkan states, and viewed Bulgarian influence in the area as the greatest threat to Greek interests.

[33][43] In 1913, the town was annexed and the treaties of London and Bucharest formally recognised Kastoria and the wider area as part of Greece.

It was nearly captured by the Communist Democratic Army of Greece in 1948, and the final battles of the civil war took place on the nearby Mount Gramos in 1949.

[52] A Kastorian Greek diaspora numbering 10,000 in the 1980s established itself in Frankfurt after it replaced Leipzig as Germany's new fur industry centre, following its post–war division.

Indeed, (as mentioned above) the town was possibly named after one of the former staples of the trade – the European beaver (kastóri in Greek), now extinct in the area.

[53] Involvement with fur began in the early middle ages, when Kastoria supplied ermine pelts for the robes of Byzantine courtiers.

[52] The fur industry was established in Kastoria during the sixteenth century, and extensive trade links emerged connecting the town with wider Europe.

[64] According to the findings of Dimitri Mishev, the town had a population of 4,000 Greek Christians, 400 Bulgarian Patriarchist Grecomans and 72 Vlachs in 1905 (excluding the Muslim minority).

[70] At the time of the First Bulgarian Empire, Kastoria had a significant Romaniote Jewish community, with prominent individuals such as scholar Tobiah ben Eliezer.

[25] Following the conquest and depopulation of Constantinople, the Romaniote Jews from Kastoria led by Matthias Tamar, were forcefully resettled by the Ottomans in Balat district as part of efforts to repopulate the city.

[28] Toward the end of the 15th century, Jews expelled from Italy, Sicily, Portugal and Spain settled in Kastoria and became an important part of the population.

[30] In the late seventeenth century, the Jewish messianic Sabbatean movement had some prominent supporters in Kastoria, although most remained as practicing Jews.

Kastoria originally had 72 Byzantine and medieval churches, of which 54 have survived;[3] including Panagia Koumpelidiki and St Athanasius of Mouzaki.

During this time, the processing and exporting of animal furs to Europe created wealth, and city mansions, of particular architectural and decorative value, were built.

This interconnected nexus of churches and private houses constitutes a rare example of a Byzantine and post-Byzantine township, and remains inhabited to this day.

The traditional buildings and manor houses of the "Doltso" and "Apozari" neighbourhoods are threatened by modern development in the city, as well as structural degradation from poor levels of conservation.

[97] Prior to Muslims leaving Kastoria, its last imam sold the mosque and under Greece has been used as a museum and as an antiquities warehouse, closed to the public.

[108] The Madrassa, a theological school with an open courtyard was declared a preserved monument by Greece in 1925 and repurposed as a depot for salt and other products.

[111] The Mathioudakis barracks, a military Ottoman structure from the early twentieth century was used from the interwar period to 2006 by the Greek army, who also erected several buildings within the complex.

[112] The Mathioudakis barracks now belongs to Kastoria municipality who has sought to demolish and rebuild it as a police station with pushback from town locals who advocate for its preservation.

[110] Muslims left Kastoria following the population exchange in 1923 and a new urban plan modernised and changed the town's architectural layout and space.

[110] The period of the 1930s brought some architectural alterations and overall the town retained its traditional form until the 1960s when new construction proceeded in an anarchic manner changing Kastoria.