Cithaeron rises on the border between Boeotia and Attica, a long mountain ridge that separates the plain of Thebes from the territory of Athens and Plataea. Its peaks are rugged and its slopes are thick with pine and cedar, a wilderness that has always been the boundary between civilisation and the wild. In the earliest times, the mountain was sacred to the old gods of the Boeotian countryside, but by the classical period it had become above all the mountain of Dionysus, the god of wine and ecstasy who was said to have been born a second time on its slopes. The village of Eleutherae, which clung to its northern flanks, was famous for its Dionysian cult, and the masks and rituals of Eleutherae eventually became the foundation of Athenian tragedy.

The most famous child of Cithaeron was not born there but abandoned there. Oedipus was the son of Laius, the king of Thebes, and of Jocasta. An oracle had warned Laius that his son would one day kill him and marry his own mother. When Jocasta gave birth, Laius pierced the infant's ankles with a spike, bound them together with leather thongs - which is why the boy was called Oedipus, Swollen-Foot - and ordered a shepherd to expose him on the slopes of Cithaeron. The shepherd, unable to kill the child, left him on the mountain and reported that the wolves had taken him. But a Corinthian shepherd found the infant, rescued him, and carried him to Polybus and Merope, the king and queen of Corinth, who raised him as their own. Years later, Oedipus would unknowingly fulfil the prophecy, killing Laius at a crossroads and marrying Jocasta, not knowing that the woman he loved was his own mother. The mountain where he had been left to die became the symbol of the fate that no human cunning can escape.

Cithaeron was also the place where Heracles committed his most terrible crime. Hera, the queen of Olympus and goddess of marriage, had hated Heracles from the moment of his birth because he was the son of her husband Zeus and the mortal woman Alcmene. She pursued him with madness throughout his life, and on one occasion she drove him into a frenzy so complete that he could not recognise his own family. On the slopes of Cithaeron, Heracles seized his wife Megara and their children and killed them with his bare hands, or in some versions with arrows, believing them to be enemies. When the madness passed and he saw what he had done, he was overcome with grief. He went to Delphi, where the oracle of Apollo told him that he must serve Eurystheus, the king of Mycenae, for twelve years and perform twelve labours as expiation. The mountain where he had destroyed his family became the starting point of the greatest heroic career in Greek mythology.

The mountain's most terrible myth is the death of Pentheus. Pentheus was the king of Thebes, the grandson of Cadmus, the Phoenician prince who had founded the city. He was a young and arrogant ruler who refused to acknowledge the divinity of Dionysus, his own cousin, the son of Semele and Zeus. When Dionysus returned to Thebes from the East, bringing his frenzied worshippers, the Maenads, with him, Pentheus tried to suppress the cult. He arrested the god's followers and mocked the new religion. Dionysus, in revenge, drove Pentheus mad and lured him to Cithaeron, disguising him in women's clothing so that the Maenads would take him for one of their own. Pentheus climbed a pine tree to spy on the women's secret rites, but the Maenads discovered him. Led by his own mother Agave, who was in the grip of Dionysian frenzy, they tore him limb from limb. Agave carried his severed head down the mountain on her thyrsus, believing it to be the head of a lion, and presented it to her father Cadmus in triumph. Only when the frenzy passed did she realise what she had done. The mountain that had witnessed the exposure of Oedipus now witnessed the dismemberment of his descendant, a chain of violence that seemed to cling to the very rocks of Cithaeron.

Actaeon, too, met his end on Cithaeron. He was a Theban hunter, the grandson of Cadmus, who had been raised by Chiron, the wise centaur on Mount Pelion. One day, while hunting on Cithaeron, he stumbled upon Artemis, the virgin goddess of the hunt, bathing in a sacred spring with her nymphs. The goddess, enraged at being seen naked by a mortal, transformed him into a stag on the spot. His own hounds, no longer recognising their master, fell upon him and tore him to pieces. The hunter who had been trained by the greatest teacher in Greece died on the same mountain where Pentheus would later be dismembered, a victim of divine wrath that brooked no intrusion.

Despite its reputation for violence, Cithaeron was also a place of worship. The Dionysian festivals held on its slopes were among the most important religious events in Boeotia. Every year, the women of Thebes and the surrounding villages would climb the mountain in procession, carrying thyrsi wreathed with ivy and vine, and dance in honour of the god. The mountain was believed to be the place where Dionysus had been born a second time, after Hera had driven his mother Semele mad and Zeus had rescued the unborn god by sewing him into his own thigh. In the Hellenistic and Roman periods, the cult continued, and Pausanias, the Greek traveller who walked through Greece in the 2nd century CE, reported that the mountain was still sacred to Dionysus and that its caves were still visited by worshippers.