Origins and the search for them define many parts of the Theban story. Cadmus, for instance, sowed the teeth of a dragon and thereby produced inhabitants of Thebes. Those sprung from these teeth had, according to Aristotle, a spear-shaped birthmark in order to indicate their lineage (Poetics 1454b22). In addition, questions about the parentage of both Dionysus and Oedipus led to catastrophic results. For his part, Statius' interest in origins has to do with identifying an appropriate beginning for his Theban tale:

Shall I sing of the origins of the dreadful clan, the Sidonian rape, the unrelenting demand of Agenor's order, and Cadmus searching the seas? The story goes back a long way, if I should tell about the nervous farmer of hidden war who buried battles in unspeakable furrows, and then follow upon that in full detail: by what song Amphion ordered mountains to approach Tyrian walls, why Bacchus had fierce hatred towards his ancestral city, what cruel Juno did, against whom wretched Athamas took up his bow, and why Palaemon's mother did not fear the huge Ionian sea as she was about to plunge into it with him. Now I shall allow the sorrows and good times of Cadmus to have passed …