Isaac is one of the variant spellings of Eisig that I have been researching.
I have found that in my family the surname Isaac can take many forms and can
be found as Eisik, Eisyk, Eisig and Essig.
I have found these spelling variants in the Lviv and in Tarnopol areas
I understand that the original surname was Eisyk which most of the family
changed to Eisig. My Grandfather changed >from Eisyk to Eisig in Europe
and to Isaac sometime during the first 5 years in this country. I do not
know why he did so but it certainly was not to create an English heritage,
with his heavy Yiddish accent.
Errol Schneegurt eslviv@... NY