Too much drama!

On this date, November 23, in 534 B.C.E, Thespis of Icaria became the first actor (known to history) to play a character onstage according to Aristotle. (Other ancient sources make similar, though somewhat different, claims.)

Thespis was a singer of dithyrambs (songs about stories from mythology with choric refrains). He is credited with introducing a new style in which one singer or actor performed the words of individual characters in the stories, distinguishing between the characters with the aid of different masks. This new style was called tragedy, and Thespis was the most popular exponent of it. Eventually, in 534 BC competitions to find the best tragedy were instituted at the City Dionysia in Athens, and Thespis won the first documented competition. 

He is said to have traveled from town to town, carrying his props and masks with him in a cart.
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It is generally believed that there were others prior to Thespis who had performed as individuals, but no names have come down to us. Perhaps the real import of this tradition is that Thespis was the first successful self-promoter in the world of drama. Or that there is another unknown first in the background-- a publicist!