Dionysus delivers the opening monologue, announcing that he has returned to Thebes from Asia to reveal his godhead and institute his worship. His mother’s sisters have denied his divinity, as has Pentheus, the current ruler of Thebes. Dionysus intends to teach them what happens to a city that “lacks the blessing of my rites” (129). To do so, he has assumed a mortal disguise, presenting himself as a priest of Dionysus from Lydia. His Bacchants (who make up the Chorus) have traveled with him from Asia. They enter, chanting the story of Dionysus’ divine birth, instructing Thebes to worship him, and describing how he will spur on his Bacchants. Teiresias enters searching for Cadmus, who agreed to worship Dionysus with him, then Cadmus enters. He is eager for guidance, and Teiresias instructs him, telling Cadmus that only they two have accepted Dionysus. Cadmus asserts his submission to the gods.

Pentheus enters. Having heard of “strange goings-on,” he has returned to Thebes and captured some of the women who claim to be serving Dionysus but who he believes are worshipping Aphrodite (133).