 As a colony Trapezous initially paid tribute to Sinope, but early banking (money-changing) activity is suggested occurring in the city already in the 4th century BCE, according to a silver drachma coin from Trapezus in the British Museum, London.Cyrus the Great added the city to the Achaemenid Empire, and was possibly the first ruler to consolidate the eastern Black Sea region into a single political entity (a satrapy).Trebizond's trade partners included the Mossynoeci.