d down by its three great masters made in
most respects by the Roman imitators of these poets and of their
successors.

Subjects of Greek tragedy.

Tragedy was defined by Plato as an imitation of the noblest life. Its
proper themes--the deeds and sufferings of heroes--were familiar to
audiences intimately acquainted with the mythology of the national
religion. To such themes Greek tragedy almost wholly confined itself;
and in later days there were numerous books which discussed these myths
of the tragedians. They only very exceptionally treated historic themes,
though one great national calamity,[60] and a yet greater national
victory,[61] and in later times a few other historical subjects,[62]
were brought upon the stage. Such veiled historical allusions as
critical ingenuity has sought not only in passages but in the entire
themes of other Attic tragedies[63] cannot, of course, even if accepted
as such, stamp the plays in which they occur as historic dramas. No
doubt Attic tragedy, though after a different and more decorous fashion,
shared the tendency of her comic sister to introduce allusions to
contemporary events and persons; and the indulgence of this tendency was
facilitated by the revision ([Greek: diaskeue]) to which the works of
the great poets were subjected by them, or by those who produced their
works after them.[64] So far as we know, the subjects of the tragedies
before Aeschylus were derived from the epos; and it was a famous saying
of this poet that his dramas were "but dry scraps from the great
banquets of Homer"--an expression which may be understood as including
the poems which belong to the so-called Homeric cycles. Sophocles,
Euripides and their successors likewise resorted to the Trojan, and also
to the Heraclean and the Thesean myths, and to Attic legend in general,
as well as to Theban, to which already Aeschylus had had recourse, and
to the side or subsidiary myths connected with these several groups.
These substantially remained to the last the themes of Greek tragedy,
the Trojan myths always retaining so prominent a place that Lucian could
jest on the universality of their dominion. Purely invented subjects
were occasionally treated by the later tragedians; of this innovation
Agathon was the originator.[65]

Construction.

The Aeschylean trilogy.

The tetralogy.

Complicated actions.

Thespis is said to have introduced the use of a "prologue" and a
"rhesis" (speech)--