Euripides' play the Bacchae was written after 407 BCE towards the end of the playwright's life while he was in voluntary exile in Macedon and was performed in Athens some time after his death in 406 BCE.
The action takes place in the ancient Greek city of Thebes. The god Dionysus arrives disguised as a mortal. He is the god of wine also of singing and dancing, and the theatre. He has come to punish Thebes and it's king, Pentheus, for failing to worship him. Now Dionysus and Pentheus are actually related. Dionysus' mother (who died when he was born) was the sister of Pentheus' mother; so he and Pentheus are cousins. This makes Pentheus' refusal to recognise his divinity, and also the refusal of his aunts, including Agaue, Pentheus' mother, all the more insulting.
They are asking for trouble and Dionysus has already started to take his revenge by driving all the women of Thebes mad (including his aunts) and sending them to the mountains. Here they live like maenads, that is wild women who worship the god with ecstatic dancing, hunting animals and eating the flesh raw.
Not all the Thebans are denying the god, however. Early on in the play we see two very old men, dressed in the proper clothes for bacchic worship. They are Tiresias, the blind prophet and Cadmus, the original founder of Thebes who has now handed over the kingship to his grandson, Pentheus. It seems that the god expects everyone, young and old to dance and the two old men express great enthusiasm for the idea, although Cadmus wonders if it might be better to go by coach to the mountain where the rituals are taking place.
Thebes itself is over run with Dionysus' own band of followers, again maenads but these are women who have come with him from the East, singing and dancing to the beat of drums. Pentheus arrives determined to re-establish order. He catches sight of the two old men. Pentheus dismisses the attempts of Tiresias and Cadmus to change his mind and sends his guards off to imprison the maenads and capture their mysterious leader.
A guard arrives with the disguised god as a prisoner with his hands bound. The guard though speaks of the miraculous escape of some of the captured maenads. Pentheus, true to form, ignores this and now tries to engage in a battle of wits with the stranger. Finally, Pentheus enraged, orders that Dionysus be taken away to a prison cell before himself entering the palace.
Dionysus' band of maenads now dance, they speak of the king's anger and call on the god to save them. In answer the god calls out to them, before sending an earthquake that brings the palace tumbling down and then Dionysus, still in disguise, enters and tells them how he fooled the king and made his escape.
Pentheus enters, mystified by the stranger's escape but still unrepentant. A herdsman arrives with news of the maenads on the mountains and describes an idyllic scene that only turns violent when a group of men tries to capture the women. Again although the herdsman describes miraculous occurrences, Pentheus remains inflexible and for a third time he tries to outwit the god in a battle of words. Finally, Dionysus takes possession of him and tricks him into agreeing to dress up in women's clothes in order to go and spy on the maenads in the mountains.
A messenger gives a horrific account of the king's death on the mountain, dismembered by his own mother and his aunts. Agaue arrives carrying her son's head, believing it to be a lion cub that she has hunted down and killed with her bare hands. Her father Cadmus brings the rest of Pentheus' body, all that he hasbeen able to gather up from the mountain side. Slowly he manages to bring Agaue back to her senses and to the enormity of what she has done whilst possessed by the god. Horrified, aware that her polluted hands are unworthy to touch her son's body, she nevertheless, composes it for burial.
The god appears now in his true form and pronounces the fate each is to suffer including banishment from their native country. Cadmus speaks out against the harshness of their punishment: gods should behave better than this. After a moving farewell father and daughter depart on their separate ways, Agaue throwing down her maenad regalia and renouncing all things bacchic. The chorus of maenads speak the last words- things do not happen as we expect them to and the gods bring about the improbable- an observation of the unpredictability of human existence in the face of forces beyond our comprehension or a trite summing up preparatory to getting back to normal life?