King of Thebes Cadmus abdicated in favour of his grandson Pentheus due to his old age. Pentheus soon banned the worship of the god Dionysus, who was the son of his aunt Semele, and didn't allow the women of Cadmeia to join in his rites.
Dionysus, angered, caused Pentheus' mother and his aunts, Ino and Agave, along with all the other women of Thebes, to rush to Mount Cithaeron in a bacchic frenzy. Because of this, Pentheus imprisoned Dionysus, but his chains fell off and the jail doors opened for him.
Dionysus then lured Pentheus out to spy on the bacchic rites. The daughters of Cadmus saw him in a tree and thought him to be a wild animal. Pentheus was pulled down and torn limb from limb by them (sparagmos), causing them to be exiled from Thebes.
The name 'Pentheus', as Dionysus and Teiresias both point out, means "'Man of Sorrows" and derives from πένθος, pénthos, sorrow or grief, especially the grief caused by the death of a loved one; even his name destines him for tragedy. Pentheus was succeeded by his uncle Polydorus.