Just viewed the first of a twelve part series titled “Russia’s Forgotten Wars”. The link will take you to –
The Campaigns of Svyatoslav, and is well worth watching. In Russian with English subtitles.
From the description: “Forgotten Wars of Russia" is a series of documentary films about armed conflicts that the Russian state entered from the time of the baptism of Russia to the Patriotic War of 1812. Over the years, Russia has been confronted by the strongest powers: Byzantium, Sweden, the Ottoman Empire, Persia, the Golden Horde…”