Sudak is a historic townlet in Crimea, situated 57 km to the west of Theodosia and 104 km to the east of Simferopol. Today it is a popular resort, best known for its Genoese fortress, the best preserved on the northern shore of the Black Sea.

Sudak was founded by Greek merchants from Byzantium in the 3rd century AD. The original Greek name for the city was Sougdeia, meaning "Sogdian". The Khazars pronounced its name as Sugdak, the Slavs as Surozh, and the Italians as Soldaia. The Life of St. Stephen of Surozh describes the 8th-century town as a dependency of the Byzantine Empire. About 800, it was supposedly attacked by the Rus chieftain, Bravlin. It is thought that the Khazars retained the town from the early 800s until 1016, when the Byzantines finally defeated the local warlord Georgius Tzul. Afterwards, the town seems to have preserved some sort of autonomy within the Byzantine Empire.

Stronghold in Sudak
Stronghold in Sudak

The Mongols further damaged its prosperity in 1223 and 1239. The Seljuk Sultanate of Iconium army and fleet from Sinop held and fortified Sudak in 1224. Several years later, the site was occupied by the Venetians, who ceded it to Genoese control in 1365. The Ottomans wrestled it from the Genoese in 1475 and, after much looting, gave to the Crimean Khanate. In 1771, Sudak was occupied by Rumyantsev's army. 12 years later, it definitively passed to the Russian Empire.
(Sources: Wikipedia)