Aeschylus is considered the first of the three greatest ancient Greek tragedians, alongside Sophocles and Euripides.
Born at Eleusis in Attica, he wrote his first play at ay age 27 although the earliest surviving play is The Persians, performed in 472 BC. The writer had a significant military career prior to becoming a writer. In 490 BC, he fought in the Battle of Marathon, and 10 years later was a fighter at the Battle of Salamis, both significant battles against Persia. Salamis was the subject of the play The Persians
According to legend, Aeschylus was killed in 456 BC when an eagle mistook the playwright’s head for a stone dropped a tortoise on his head.
Aeschylus is known to have written 76 plays although only six of which remain.
They are The Persians (472 BC), Seven Against Thebes (467 BC) The Suppliants (463 BC?) Agamemnon, The Libation Bearers, The Eumenides (458).
Prometheus Bound was often attributed to Aeschylus although the authorship is now subject to debate.
Agamemnon, The Libation Bearers, and The Eumenides  are collectively called The Oresteia  and is a trilogy of tragedies about the end of the curse on the House of Atreus.
It is the only surviving trilogy of ancient Greek plays, although the fourth satyr play that would have been performed with it has not survived. The trilogy was originally performed at the Dionysia festival in Athens in 458 BC, where it won first prize. During Aeschylus’ lifetime dramatic competitions were held at the Festival of Dionysus. Playwrights submitted four plays --  three tragedies and a lighter ‘satyr’ play. The great poets of the day competed for the prizes each year.
These plays, while steeped in the stories of the Trojan wars and full of gods, tackle the modern and complex issue of justice and the change from a form of justice built around personal revenge to one of justice by trial. It is indicative of an evolving society governed by reason.  Justice is decided by a jury of peers, and conducted by judges representing the society. In these plays this is sanctioned by the gods. This theme of the people self-governed by consent through law, as opposed to tribalism and superstition, recurs throughout Greek art and philosophy.
The concept of an objective and impartial court marks the end of the continuous cycle of vengeance and revenge which marks the former system of justice.

The Orestia (Spoiler Alert)

Agamemnon details the return of Agamemnon, King of Argos, from the Trojan War. Prior to leaving for Troy, Agamemnon had sacrificed his daughter Iphigenia to the gods at their direction.  Clytemnestra, his wife, spends the 10 years of the king’s absence planning his death as revenge for the killing of Iphigenia. Clytemnestra has also continued an adulterous relationship with Aegisthus, Agamemnon's cousin.
Agamemnon returns with a concubine, the prophetess Cassandra, the daughter of King Priam of Troy whom Apollo has cursed, giving her the gift of clairvoyance, but on the condition that no one who hears her believes her.
In vengeance for Iphigenia, rage at the presence of Cassandra and at the urgings of Aegisthus, Clytemnestra murders Agamemnon in his bath. Cassandra is murdered next. The play ends with the chorus warning that Agamemnon’s son Orestes will surely return to exact vengeance.
In the second play, The Libation Bearers, Clytemnestra, in bed with her lover Aegisthus, is disturbed by nightmares. She orders her daughter Electra, whom she has reduced to the status of a slave, to pour “libations” on Agamemnon's grave to salve her guilt.
At the grave she comes upon a stranger whom she discovers is her long lost brother --Orestes back in Argos for revenge. The two siblings plot the murder of their mother and the usurper Aegisthus.
After much discussion on the right of matricide, Orestes kills both Aegisthus and his mother. But as soon as he exits the palace he set upon by the Furies who haunt and torture him for his crime. He flees.
The Eumenides, or the Furies, is the final chapter of the Orestia trilogy and sees Orestes still fleeing the furies, god like creatures who avenge patricide and matricide. He finds a refuge in temple of Delphi, and the god. Apollo is unable to free Orestes from the Furies' wrath, but does help him escape to Athens by putting the furies to sleep for a short time. The ghost of Clytemnestra's wakes the furies who angrily track Orestes to Athens.
Finally the Godess Athena intervenes and orders a jury of twelve Athenians to judge her Orestes. Apollo acts as defender or Orestes, while the Furies act prosecutors. The trial results in a hung jury and Athena breaks the tie by voting in favour of Orestes. Athena then decrees that henceforth hung juries must result in acquittal.