Why were masks used in greek theatre?

Masks were originally used in Greek theatre to help the audience separate the identity of the actor from the identity of the character. With the masks on, the actors were no longer themselves, but the characters they were portraying.

on the morning of  july 21,  1861, general mcdowell ordered the  unionarmy to attack. it was on this hill that  confederate  colonel thomas jackson and his forces held back theunion  troops.