Aeschylus (c. 525/524 BC-c.456/455 BC), an ancient Greek playwright, is known as the father of tragedy because his plays are the earliest surviving examples of that genre. In his work he presented evil as vivid and tragic, and time as a key element of progress and healing. Aristotle stated that Aeschylus was the first to expand the number of characters in a play in order to create conflict between characters rather than through the use of the chorus. Seven of his many plays survive today.