Aeschylus ( or ; Aiskhulos; ; c. 525/524 – c. 456/455 BC) was an ancient Greek tragedian. He is also the first whose plays still survive; the others are Sophocles and Euripides. He is often described as the father of tragedy: critics and scholars' knowledge of the genre begins with his work, and understanding of earlier tragedies is largely based on inferences from his surviving plays. According to Aristotle, he expanded the number of characters in theater to allow conflict among them, whereas characters previously had interacted only with the chorus.