Although Professor Murray in his edition of Aeschylus' plays puts Prometheus between Persae (472 b.c.) and Septem (467 b.c.), many students nowadays show a tendency to place it in the last period of the poet's work. For instance Mr. W. F. J. Knight (J.H.S. lviii, 1938, p. 53) says:
‘It is important to regard all the extant plays of Aeschylus, and at least some of the plays that are lost, as a single sequence of developing poetic thought. Accordingly, at the end, when Aeschylus solves the hardest problem of all, the marriage of Heaven and Earth, something like the Prometheia with a satanic Zeus might almost have been predicted…. In fact the metaphysical argument may even have some force in determining the date and authenticity of the Prometheia.