The Trapezuntine Empire was formed in 1204 with the help of Queen Tamar of Georgia after the Georgian expedition in Chaldia and Paphlagonia,[3] which was commanded by Alexios Komnenos a few weeks before the Sack of Constantinople.

Due to its natural harbours, defensible topography and access to silver and copper mines, Trebizond became the pre-eminent Greek colony on the eastern Black Sea shore soon after its founding.

[12] The rulers of Trebizond called themselves Megas Komnenos ("Great Comnenus") and – like their counterparts in the other two Byzantine successor states, the Empire of Nicaea and the Despotate of Epirus – initially claimed supremacy as "Emperor and Autocrat of the Romans".

Anthony Bryer has argued that six of the seven banda of the theme "district" of Chaldia were maintained in working order by the rulers of Trebizond until the end of the empire, helped by geography.

Geography also defined the southern border of this state: the Pontic Alps served as a barrier first to Seljuk Turks and later to Turkmens, whose predations were reduced to a volume that the emperors could cope with.

Chaldia had already shown its separatist tendencies in the 10th and 11th centuries when it came under the control of a local leader named Theodore Gabras, who according to Anna Komnene regarded Trebizond and its hinterlands "as a prize which had fallen to his own lot" and conducted himself as an independent prince.

[18] Another successor to Theodore was Constantine Gabras, whom Niketas describes as ruling Trebizond as a tyrant, and whose actions led Emperor John II Komnenos in 1139 to lead an expedition against him.

[19] The empire traces its foundation to April 1204, when Alexios Komnenos and his brother David took advantage of the preoccupation of the central Byzantine government with the encampment of the soldiers of the Fourth Crusade outside their walls (June 1203 – mid-April 1204) and seized the city of Trebizond and the surrounding province of Chaldia with troops provided by their relative, Tamar of Georgia.

Alexios and his brother, David, ended up at the court of Queen Tamar of Georgia, who gave them military support to return to Byzantine territory.

Vasiliev explains that she had been motivated to do so after the Emperor Alexios III Angelos stole the gifts Tamar had given to a group of visiting monks as they passed through Constantinople.

Sergey Karpov has identified a lead seal of Alexios, on one side "the image of a strategos in the peaked helmet led by hand by St. George" with the inscriptions Ἀλέξιος ὁ Κομνηνός [Alexios Komnenos] and Ὁ Ἅ(γιος) Γεώργιος [Saint George] on either side; on the obverse is a scene of Ἡ Ἁγία Ἀνάστασις [The Holy Resurrection] with the corresponding inscription.

Karpov interprets the significance of this image and the inscription as portraying the most important achievement of his life, St. George inviting the victorious prince to enter Trebizond and opening the gates of the city with his left hand.

The common view is that the Empire of Trebizond relied heavily upon wealth gained from its trade with Genoese and Venetian merchants to secure for itself the resources necessary to maintain independence.

The destruction of Baghdad by Hulagu Khan in 1258 diverted the western terminus of the Silk Road north to the Black Sea, and due to its link with their local capital at Tabriz, Trebizond accumulated tremendous wealth under the suzerainty of the Mongols.

The troubled reign of Manuel's youngest son John II (1280–1297) included a reconciliation with the restored Byzantine Empire and the end of Trapezuntine claims to Constantinople.

Bending under the weight of the disasters that accumulated on his states, Emperor Michael abdicated in 1349 in favor of his nephew, Alexios III, who gradually brought the partisans of both factions under control.

[citation needed] Under the rule of Alexios III, Trebizond was considered an important trade center and was renowned for its great wealth and artistic accomplishment.

This threat was not from the small Turkmen emirates that bordered Trebizond, but from the dynasty of the Osmanli, a new Turkish power emerging from western Anatolia that would soon consolidate the Ottoman Empire.

Although their expansion was temporarily checked by Tamerlane at the Battle of Ankara in 1402, by the 1430s the Ottomans had recovered their fortunes, seizing large segments of Greece and finally capturing Constantinople itself on 29 May 1453.

[33] While Murad's son and successor, Mehmed II, was away laying siege to Belgrade in 1456, the Ottoman governor of Amasya attacked Trebizond, and although defeated, he took many prisoners and extracted a heavy tribute.

He gave his daughter Theodora (also known by the name of Despina Khatun) to the son of his brother-in-law, Uzun Hasan, khan of the Ak Koyunlu, in return for his promise to defend Trebizond.

According to the Acts of Vazelon, which were written by contemporary monks, most peasants in the Matzouka region of the Empire had first names relating to Christian religious figures.

[39] The Empire of Trebizond acquired a reputation in Western Europe for being "enriched by the trade from Persia and the East that passed through its capital," according to Steven Runciman, "and by the silver-mines in the hills behind, and famed for the beauty of its princesses.

"[40] Donald Nicol echoes Runciman's observations: "Most of the emperors were blessed with a progeny of marriageable daughters, and the beauty of the ladies of Trebizond was as legendary as the wealth of their dowries.