
In early 1318 Pope John XXII established a Latin Church diocese of Kaffa, as a suffragan of Genoa. Ibn Battuta visited the city, noting it was a "great city along the sea coast inhabited by Christians, most of them Genoese." He further stated, "We went down to its port, where we saw a wonderful harbor with about two hundred vessels in it, both ships of war and trading vessels, small and large, for it is one of the world's celebrated ports." The Great Soviet Encyclopedia also adds that the city of Caffa was established during the times when the area was ruled by the Khan of the Golden Horde Mengu-Timur.

It came to house one of Europe's biggest slave markets. They established a flourishing trading settlement called Kaffa, which virtually monopolized trade in the Black Sea region and served as a major port and administrative center for the Genoese settlements around the Sea. In the late 13th century, traders from the Republic of Genoa arrived and purchased the city from the ruling Golden Horde. The Genoese ports and later Turkish-controlled area were south of the mountains. Likely, from the 9th century there were Cumans and Goths living alongside the Greeks, and by 1270s, perhaps some Tatars and Armenians as well. A small local Greek population must have existed in situ and in the neighboring settlements. However, the population had become completely agrarian. The archaeological evidence indicates that during the Middle Ages the population about Theodosia never decreased to zero several medieval churches are found in the area dating from the times of Late Antiquity/ Early Middle Ages.

Like the rest of Crimea, this place (village) fell under the domination of the Kipchaks and was conquered by the Mongols in the 1230s.Ī settlement named Kaphâs (alternate romanized spelling Cafâs, Greek: Καφᾶς) existed surrounding Theodosia prior to the penetration of Genoese into the Black Sea. It was at times part of the sphere of influence of the Khazars (excavations have revealed Khazar artifacts dating back to the 9th century) and of the Byzantine Empire.

Theodosia remained a minor village for much of the next nine hundred years. Noted for its rich agricultural lands, on which its trade depended, the city was destroyed by the Huns in the 4th century AD. The city was founded as Theodosia (Θεοδοσία) by Greek colonists from Miletos in the 6th century BC.

Theodosia and other Greek colonies along the north coast of the Black Sea from the 8th to the 3rd century BC
