a historical figure or an historical figure??
I'd say it's a historical figure, but I've read an historical X in the internet.
I'm not sure, but the d*m rule says:
"an" precedes words that begin with vowel sounds
...and since the "h" in historical isn't silent, it should be an "a"
the same happens to hour, whether you search the internet, you eventually will find both structures:
What'd a teacher say?