Nevertheless the poem on Morals and the instructions in Oratory, which
were found among the writings of Cato, may be regarded as the Roman
quintessence or, if the expression be preferred, the Roman -caput
mortuum- of Greek philosophy and rhetoric.
The immediate sources
whence Cato drew were, in the case of the poem on Morals, presumably
the Pythagorean writings on morals (along with, as a matter of course,
due commendation of the simple ancestral habits), and, in the case of
the book on Oratory, the speeches in Thucydides and more especially
the orations of Demosthenes, all of which Cato zealously studied.
Of the spirit of these manuals we may form some idea from the golden
oratorical rule, oftener quoted than followed by posterity, "to think
of the matter and leave the words to follow from it."(68)