The English word Igor was originally Ihor with an H.
The name Ihor was of the Norsemen who established Kievan Rus. Neither they nor the surrounding inhabitants were the ethnic Russians of today. The name Ihor became part of the native Ukrainian language. When the Norsemen migrated northeast into Belarus it also became part of the modern Russian language, as did the word Rus.
But the Russian language has no sound like the English H, and it became pronounced G.
This pronunciation became known in the Universal film character Igor the hunchback.