[3] He send his son to study at the Novgorod-Siversky Bursa, and later at the Chernihiv Theological Seminary, where Mazepa first got acquainted with the works of Karl Marx and Friedrich Engels, and received a reputation of a Social Democrat.

[6] As the most active member of the party, he was delegated to Kyiv in 1907 to participate in an illegal congress of the USDRP from the St. Petersburg organization.

At the same time, he established contacts with the local illegal USDRP organization, which launched extensive anti-war propaganda.

[8] In January 1919, Mazepa was a deputy of the Labor Congress of Ukraine, and from April 1919 he was the Minister of Internal Affairs of the Ukrainian People's Republic in the government of Borys Martos.

[5] From 1920 Mazepa lived in exile in Lviv, where he edited the USDRP newspaper The Free Ukraine and the magazine Socialist Thought.

He defended Ukrainian interests at many social democratic conferences, was a member of the executive committee of the Labour and Socialist Internationals.

In 1945 Mazepa's wife Natalia Singalevich and two of their grandchildren tragically died during a raid on Prague by American aircraft.