and they came to Trebizond by sea,
a city inhabited by Greeks and colony of Sinope in the land of the Colchians.
They remained for almost 30 days in the Colchians villages
Xenophon, Anabasis of Cyrus, 4.8.22
According to Xenophon’s narration, in 400 B.C. the Ten Thousand reached Trebizond, where they were warmly greeted. It is the first reference of the city in the work of the Greek historian, who informs us about its foundation by inhabitants of Sinope, who were also colonists from Miletus. The precise date of foundation is not known, since the year 757/6 B.C., which is supported in the sources, is doubtful.
Built on three hills at the north foothills of Mount Minthrion (now called Boztepe), Trebizond probably owes its name to the smoothness of its ground just like the surface of a trapezium or to the shape of its acropolis. Its geographic position on the southeast coast of the Black Sea and on a naturally fortified location with a relatively safe port contributed to its economic growth.
The dependence of ancient Trebizond to its metropolis, Sinope, is evident from the payment of tribute till the end of the 5th century. From then and in the next century, the city flourished and managed to mint its own coin. Despite the lack of information, it seems that till the age of the Epigoni of Alexander the Great, Trebizond was largely independent. The city has met prosperity during the years of the Mithridate Kings, especially under Mithridates VI Eupator (120-63 B.C.), and it was declared a free city and an ally of the Romans. However, after the support of Niger against Septimius Severus (193-211 A.D.) and the victory of the last at the end of the 2nd century A.D., Trebizond lost all of its privileges. Later, in 260 A.D., it suffered many damages caused by the raids of Alans and Sarmatians.
The transport of the capital of Pontus from Neokaisareia to Trebizond happened in the years of Justinian (527-565). Trebizond, during the 8th century and with the establishment of the thematic division, became the capital of the Theme of Chaldia. In 1071 the city was occupied by Seljuk Turks, who in the same year defeated the Byzantine troops of Romanos IV Diogenes (1068-1071) in Manzikert. It was liberated in 1075 from the duke Theodoros Gavras, who he and his heirs tended to render the city autonomous. The control of Pontus was stabilized in the last years of the reign of John II Komnenos (1118-1143) and Manuel I Komnenos (1143-1180).
A crucial point in the history of the city but generally of the region of Pontus was in 1204 after the occupation of Constantinople by the Latins of the Fourth Crusade. Then, the brothers Alexios and David Komnenos, grandchildren of the emperor Andronikos I (1183-1185), gained control of Trebizond and founded the Empire of Trebizond. Alexios, for reasons of emphasizing his royal origins, adopted the characterization “Megas (Grand) Komennos” and was kept by all the rulers of the state in all its 257 years. In this time, the empire has known Seljuk and Mongolian dominion, civil wars due to the disagreements of policy in favor or against Constantinople, as well as problems with the Genovese, to whom the foundation of a trade community was allowed. Despite the above, the city flourished as an important intelligence and trade center, especially after the Mongolian occupation and destruction of Baghdad in 1285, which shifted the routes of the caravans towards the Black Sea.
The Empire of Trebizond was terminated in 1461 by Mehmed II (1451-1481), who in 1463 killed the last Grand Komnenos emperor David I (1458-1461) with his sons. The Greek population of the city reduced dramatically after the Ottoman domination. However, after the mid-17th century, the population increased and prospered in the second half of the 19th century. At the beginning of the 20th century and in 1923, the Treaty of Lausanne forced them to abandon their ancestral homes. Undoubtful confirmations of the historical presence of the Greeks are the monuments, still standing in good condition or in ruins, inside and outside of the city. The examples are Hagia Sophia, Panagia Chrysokephalos and the historical monasteries of Panagia Soumela and Saint John Vazelon.