Trabzon, as it's called today, is a town in NE Anatolia. Strong greek traditions (said to be founded by settlers from Milet), later capital of the Empire of Trabzon, a successor state to the Byzantine Empire. But judging by the costumes I'd say the story plays around 400 BC, at the times of Alexander the Great when it was still part of the hellenistic world.
Thais was an Athenian courtesan who traveled with the army of Alexander the Great in its invasion of Persia. She is chiefly known from Dryden's story that she persuaded Alexander to set fire to the Achaemenian capital of Persepolis in the course of a **93** revel. An interesting novel by Iwan Yefremov ("Thais of Athens") proposes she became a priestress of Ashtoreth (whom King Solomon worshipped, 1 Kings 11.5) She's the fertility Goddess whom all Christians worship on Easter... Interesting stuff, not only when she'll get rid of that toga.