What, then, was the origin of the performance which in the fifth century constituted the final member of tetralogies? Such tetralogies cannot be made out for any playwright before Aeschylus; and the number of plays attributed to Pratinas, eighteen tragedies and thirty-two satyric dramas, throws additional doubt upon the probability that the early poets were required to present four plays together.[57] We have thus far considered three types of performances: the improvisational dithyramb, which was still continued in rural and primitive districts; the improved dithyramb (in 508 B.C. dithyrambic choruses of men were added to the program of the City Dionysia at Athens), and tragedy. The last two had by this time become semi-literary types. Now we are expressly told, and there is no reason to discredit the information, that Pratinas of Phlius in the Peloponnesus was “the first to write satyr-plays.”[58] The general situation is clear. After tragedy had lost its exclusively Bacchic themes and had considerably departed from its original character, Pratinas endeavored to satisfy religious conservatism by introducing a new manner of production, which came to be called satyric drama. This was a combination of the dramatic dithyramb of his native Phlius, which of course had developed somewhat since the days of Arion and Epigenes, and of contemporary Attic tragedy; and it had the merit of continuing, at least for a while, the Dionysiac subjects which were so appropriate to the god’s festival. It appears that at first satyr-plays were brought out independently of tragedy and in greater numbers, comparatively, than was afterward the case. But about 501 B.C. the City Dionysia was reorganized: the goat prize was abandoned; κῶμοι, i.e., the volunteer performances from which comedy was later to develop, were added to the program; and, in particular, the regulation was established that each tragic poet must present three tragedies and one satyr-play in a series. Pratinas is known to have competed against Aeschylus about 499 B.C. His innovation doubtless fell somewhere between the institution of the tragic contest in 534 B.C. and the reorganization of the festival program in 501 B.C., possibly about 515 B.C. There remains the difficult problem as to the appearance of the choreutae in the satyric drama at different periods in Athens. Fortunately the aspect of non-dramatic sileni and satyrs is fairly certain. Already on the François vase, an amphora signed by Clitias and Ergotimus and belonging to about 600-550 B.C., there are representations of three ithyphallic creatures with equine ears, hoofs, and tails (Fig. 3).[59] An inscription ΣΙΛΕΝΟΙ leaves no doubt as to the identity of the figures. Mr. A. B. Cook lists six other inscribed vases from Attica which tell a similar story.[60] None of these seven vases, however, betrays any relationship to the theater.