Gil = ???? seems to have Belarusyn roots.This surname likely evolved from the nickname BULLFINCH.Prior to introduction of Christianity among Eastern Slavs, there was a common pagan tradition of nicknaming a baby after a plant or animal.This was consistent w/pagan ideas about the natural world at the time.The bullfinch was pretty bird w/orange breast, that liked to sing.It's traits transferred themselves upon the child w/such nickname.
Later in history as surnames were mandated for the peasantry, the nickname became a surname.
Belarus too was a part of the Polish-Lithuanian Commonwealth.