I ought not to conclude this chapter without a few words concerning the manner in which act divisions arose from the alternation of choral odes and histrionic passages in ancient drama. The earliest tragedies, such as Aeschylus’ _Suppliants_ and _Persians_, began with the entrance song of the chorus, which is called the _parodus_. In later plays it was customary for one or more actors to appear before the choral parodus in a so-called _prologue_. The first instance of this which is known to us occurred in Phrynichus’ _Phoenician Women_ (476 B.C.). After the parodus came an alternation of histrionic scenes (_episodes_) and choral odes (_stasima_), concluding with a histrionic _exodus_. These are nontechnical definitions and do not cover every variation from type, but they will suffice for present purposes. Thus Aeschylus’ _Prometheus Bound_ falls into the following divisions: prologue, vss. 1-127; parodus, vss. 128-92; first episode, vss. 193-396; first stasimon, vss. 397-435; second episode, vss. 436-525; second stasimon, vss. 526-60; third episode, vss. 561-886; third stasimon, vss. 887-906; exodus, vss. 907-1093. Though the number of stasima (and of episodes) was more usually three, as in this case, there was originally no hard-and-fast rule on the subject. In several plays there were four stasima and four episodes, and in Sophocles’ _Antigone_ five of each. Therefore in a normal tragedy like the _Prometheus_ the number of histrionic divisions would be five—prologue, three episodes, and exodus. In the early plays which had no prologue the histrionic divisions fell to four—three episodes and an exodus. In several of the later plays, on the other hand, they rose to six, and in the _Antigone_ to seven. As the lack of connection between chorus and plot increased and the size and importance of choral odes diminished (see pp. 126 f., 136-49, and 168, above) there was the more excuse for ignoring the choral elements and for concentrating attention upon the histrionic divisions. The development of comedy led to similar results. The composition of an Old Comedy has already been discussed (see pp. 40 f., above). So long as the agon and the parabasis persisted, the structural differences between tragedy and comedy were unmistakable; but with the disappearance of these features early in the fourth century (see pp. 42 f., above) the assimilation of the two genres rapidly proceeded. Moreover, as the activity of the comic chorus was confined to _entr’actes_ and as their entertainment became so foreign to the plot as no longer to be written in the manuscripts but merely to be indicated by ΧΟΡΟΥ (see pp. 147 f.), this tendency to ignore the choral element in favor of the histrionic became pronounced. Now the number of histrionic divisions in Old Comedy and in New Comedy was limited to five even less frequently than in tragedy. And in either literary genre there was no more reason for such a restriction, whether on historical