Under the Deinomenids, the land and property of many common citizens had been seized; these people flooded the courts in an attempt to recover their property. Corax devised an art of rhetoric to permit ordinary men to make their cases in the courts. His chief contribution was in helping structure judicial speeches into various parts: proem, narration, statement of arguments, refutation of opposing arguments, and summary. This structure is the basis for all later rhetorical theory. His pupil Tisias is said to have developed legal rhetoric further, and may have been the teacher of Isocrates. As in the case of Socrates, all we know of the work of Corax is from references made by later writers, such as Plato, Aristotle, and Cicero. He never wrote any of his teachings himself; they were all recorded and published by his pupil, Tisias.