Hermonassa

Tmutarakan was a medieval principality of Kievan Rus' and trading town that controlled the Cimmerian Bosporus, the passage from the Black Sea to the Sea of Azov, between the late 10th and 11th centuries. Its site was the ancient Greek colony of Hermonassa founded in the mid 6th century BCE, by Mytilene, situated on the Taman peninsula, in present-day Krasnodar Krai, Russia, roughly opposite Kerch. The Khazar fortress of Tamantarkhan was built on the site in the 7th century, and became known as Tmutarakan when it came under the control of Kievan Rus'.

Source: Wikipedia