His specialty was as a historian, translator, philologist, editor, and teacher of advanced students.
In evaluating the overall significance of Ivan the Great, Fennell concludes that his reign was "militarily glorious and economically sound," and especially points to his territorial annexations and his centralized control over local rulers.
However Fennell adds that his reign was also "a period of cultural depression and spiritual barrenness.
For the sake of territorial aggrandizement he deprived his country of the fruits of Western learning and civilization.
"[1] Dimnik said of Fennell, "His achievements are unrivaled in the West, and almost so in the Soviet Union and Russia".