Originally Posted by
Pharaoh
Well, that can't be universal because we do not say "An European." And some people do put AN when the next word starts with a consonant, "An Historic occasion."
The real rule is that if the next word begins with a vowel sound, use AN. If it begins with a consonant sound, use A.
The use of "An" before historic is an historical anachronism. It comes from the days when most people in England pronounced "historic" (and many other words beginning with "h") with a silent "h." As in " 'istoric " Thus, "an 'istoric occasion" sounded more correct.