As Vladimir Putin tramples all over Ukrainian democracy, Harry Mount argues that it was the democratic system  of ancient Athens which created the conditions for the birth of theatre

When you see Aeschylus’s Oresteia, you’re witnessing not just the birth of theatre; but also the birth of western European justice.

The Oresteia is an astonishing survival. Written in 458 BC, it’s the only remaining trilogy from Ancient Greece. In fact, there was a fourth part: Proteus, a satyr play that only exists in a tiny fragment. We should be grateful for what we’ve inherited. Of the 70 to 90 plays written by Aeschylus – the earliest surviving Greek playwright – only seven remain.

And, in the Oresteia, we have all the gory, sexy ingredients of the quintessential Greek tragedy: infidelity, murder, the ultimate family squabble, revenge – and, crucially, justice, in the form of the original jury trial.

Like so much of Greek literature, the Oresteia is rooted in the Trojan War. We all know the story of Odysseus returning from Troy on a 10-year-long epic journey. But, like Odysseus, the other conquering Greek heroes had to get home, too. And one of them was Agamemnon, King of Mycenae and brother of Menelaus, husband of Helen of Troy.

When Agamemnon returns to his windswept, hilltop palace at Mycenae – in the middle of the Peloponnese, and one of the great archaeological sites of Greece – all hell breaks loose. Unlike lovely Penelope – waiting patiently for Odysseus on Ithaca while he shags his way around the Mediterranean – Agamemnon’s wife, Clytemnestra, is spitting blood.

Not surprisingly, she still hasn’t forgiven him for sacrificing their daughter, Iphigenia, on the way to the Trojan War, in order to get a favourable wind. It doesn’t help that Agamemnon has also brought back a girlfriend – Priam’s daughter, Cassandra, whose accurate predictions of the future are never believed, like the unluckiest Fleet Street columnist.

And so, with her lover, Aegisthus, Clytemnestra takes an axe to Agamemnon – killing him in the royal bath, trapping him with a net. Cassandra, Agamemnon’s mistress, also gets the chop.

The second play in the trilogy, The Libation Bearers, tells the story of Agamemnon’s daughter, Electra, and his son, Orestes – thus the collective title, the Oresteia. The whole work pivots on the agonising question that sets revenge against justice: should you spare your mother even if she kills your father? As Orestes says at the high point of the play, “Should I be ashamed to kill my mother?”

No – is Orestes’s answer, as he knifes his mother, and her lover, Aegisthus, too; not that you see him actually doing it. One of the many sophisticated devices in the Oresteia is that you never watch any of the mass blood-letting; it’s all done off-stage, with a lot of screaming, in a move that somehow makes it all the more horrifying.

The last play in the trilogy – The Eumenides or “The Kindly Ones” – determines what happens to Orestes: should he be executed for murdering his mother or acquitted for rightly avenging his father?

And it’s in this last play that you can see the foundations of the Western European legal system under construction. The action takes place on the Areopagus – the great flat chunk of limestone you can still see today in Athens, just below the Acropolis.

This rock acted as the ancient Greek court of appeal in real life – and it was also where St Paul came to preach in 54 AD. It was here, according to the New Testament, that St Paul told the Epicureans and the Stoics, “God that made the world and all things therein, seeing that he is Lord of heaven and earth, dwelleth not in temples made with hands.” A bold thing to say in the shadow of the greatest handmade temple in the world: the Parthenon.

Here, in Athens, 500 years before Christianity was born, the western European court was born. Athenian citizens acted as jurors in the Athenian courts – and that’s what happens at the end of the Oresteia. Orestes is tried for matricide by the goddess Athena, one of a jury of 12, selected by Athena from the Athenian citizens.

Apollo acts as Orestes’s defence lawyer – always handy to have a god as your barrister. And the dead Clytemnestra is represented by the Eumenides – the terrifying Furies, avenging goddesses who have been tormenting Orestes ever since the killings. The jury is split evenly – and Athena rules that, with a divided vote, Orestes should be acquitted. A happy ending, then – often the surprising result of Greek tragedies.

But, more than that, justice has trumped vengeance; and a family blood feud has been prevented by democratic justice. The Oresteia is a paean of praise, not only to justice, but also to Athens, the shining city on the hill, where democracy and people-made law were first enshrined.

This intense patriotism isn’t surprising in Aeschylus, who also happened to be a war hero. Born into a grand family, he fought in the two great Athenian battles against the Persians – at Marathon in 490 BC, and at Salamis a decade later. His brother died at Marathon.

Aeschylus’s bravery was so celebrated that, on his tombstone, his heroism at Marathon was praised but his plays weren’t mentioned, despite him winning the Dionysia, the Athenian play-writing competition, 18 times. It’s as if Tom Stoppard, as well as being Britain’s most famous playwright, also won the Victoria Cross.

It’s no coincidence that the free, democratic city Aeschylus fought for produced an explosion of untrammelled literature, art and philosophy. Because of this relative freedom of speech, Athens had double the number of literary festivals of other cities. Repressive old Sparta had nothing on erudite Athens; Communist Russia against the enlightened West.

Aeschylus’s art would not have flourished but for democracy. In 508 BC, 60 years before the Parthenon was begun, the first democratic reforms were introduced by Cleisthenes, Pericles’s great-uncle. Cleisthenes was a leading member of the Alcmaeonids – the Athenian Kennedy family – who dominated politics from the seventh to the fifth century BC. Both Pericles and the leading politician Alcibiades were Alcmaeonids. For 180 years, until Philip II of Macedon, Alexander the Great’s father, took over the city in 322 BC, Athens was the first, and possibly the last, true democracy.

It’s no coincidence that those 180 years encompassed the golden years for Athenian literature, architecture, sculpture and all-round civilisation. The basis of that democracy was simple enough. Political decisions were made by the demos, or the people, in the ekklesia, or assembly. The ekklesia was held every eight days on the Pnyx, the hill half a mile west of the Parthenon, with a carved stone speaker’s platform. it comes from puknos – “crowded”.

In fact, there’s rather a lot of space at the Pnyx. The crowded bit is thought to refer to the single entrance to the hill. Democracy was the undercurrent to the Elgin Marbles. For all the gods and goddesses on the Parthenon frieze, there wasn’t a single overbearing tyrant, king or pharaoh there.

After all that heroism and all those plays, Aeschylus’s death in 456 BC took place far from the battlefield or the theatre. While in the Sicilian city of Gela, an eagle dropped a tortoise on his bald head, mistaking it for the sort of hard rock that could crack the tortoise’s shell.

It was an unfairly comic end for the man who, more than any other, exemplified the Athenian miracle – that weird, magical combination of democracy, justice and art that shaped the world two and a half thousand years ago.

Harry Mount’s online course The Miracle of Ancient Greece is out now. He is the author of several books including Odyssey – Ancient Greece in the Footsteps of Odysseus and he is the editor of The Oldie magazine.