At the end of X century, it was a victory over the Khazar khanate, resulting in Rus annexed a small territory, which included the Peninsula of Taman, and part of the Eastern Crimea and Western Kuban land. It formed the Tmutarakan Principality, with its capital in the city of Tmutarakan (the ancient Greek city of germonassa, later Humantarian, now Taman). Most likely the name comes from the distorted old name of the city. At the end of XI century Byzantine Empire conquers the land, but the Russian reign continues for some time. Most likely it was then minted coins on behalf of the Tmutarakan Prince Oleg, imitating Byzantine. In baptism Oleg took the name Michael, so the story he came Oleg-Michael.
Some sources attribute these coins to the time of the reign of Mstislav the Daring (988-1036).
The photo shows the instances from the exposition of the State Hermitage Museum that have a number: HE-P-1-141 and IT-R-1-142.