Aeschylus was the first of the three ancient Greek tragedians whose plays can still be read or performed, the others being Sophocles and Euripides. He is often described as the father of tragedy: our knowledge of the genre begins with his work and our understanding of earlier tragedies is largely based on inferences from his surviving plays. According to Aristotle, he expanded the number of characters in plays to allow for conflict amongst them, whereas previously characters had interacted only with the chorus.
Only seven of his estimated seventy to ninety plays have survived into modern times, and there is a longstanding debate about his authorship of one of these plays, Prometheus Bound. Fragments of some other plays have survived in quotes and more continue to be discovered on Egyptian papyrus, often giving us surprising insights into his work. He was probably the first dramatist to present plays as a trilogy and his Oresteia is the only ancient example of the form to have survived.
At least one of his works was influenced by the Persian invasion of Greece, which took place during his lifetime. This play, The Persians, is the only extant classical Greek tragedy concerned with recent history and it is a useful source of information about that period. So important was the war to Aeschylus and the Greeks that, upon his death, around 456 BC, his epitaph commemorated his participation in the Greek victory at Marathon rather than his success as a playwright.