Historians are very important !
The historian is studying Benjamin Franklin
The historian was confused by the evidence presented to him. They were unable to get a definitive answer from the historian.
The historian is studying Benjamin Franklin.
The historian found a marvelous dinosaur fossil that was millions of years old
I am not writing a sentence using that word.
a sentence using the word endotracheal
This is a sentence using the word aviator.
I am saying a sentence using the word collagen.
this is a sentence using the word armchair.
She was a historian at the desert museum
a historian studies history
Both "an historian" and "a historian" are correct, but generally "a historian" is more commonly used. The use of "an historian" follows British English rules of using "an" before words that begin with a silent 'h'.