Aeschylus (UK: /ˈiːskɪləs/,[1] /ˈɛskɪləs/;[2] Greek: Αἰσχύλος Aiskhylos, pronounced [ai̯s.kʰý.los]; c. 525/524 – c. 456/455 BC) was an ancient Greek tragedian. He is often described as the father of tragedy.[3][4] Academics' knowledge of the genre begins with his work,[5] and understanding of earlier tragedies is largely based on inferences from his surviving plays.[6] According to Aristotle, he expanded the number of characters in the theater and allowed conflict among them; characters previously had interacted only with the chorus.[nb 1]