highest and most representative impersonation is unquestionably to be
found in the person of Marcus Antoninus.... Stoicism faced the whole
problem of existence, and devoted as searching an investigation to
processes of being and of thought, to physics and to dialectic, as to the
moral problems presented by the emotions and the will." [Footnote:
_Marcus Aurelius Antoninus_, in English, by Gerald H. Rendall,
Introduction, xxvii.]

Such was stoicism, of which Marcus Aurelius was and still remains the
foremost expression. He admitted that as emperor his first duty was to
sacrifice himself for the public and he did his duty with a constancy
which ultimately cost him his life. Among these duties was the great duty
of naming his successor. The Roman Empire never became strictly
hereditary. It hinged, as perhaps no other equally developed system ever
hinged, upon the personality of the emperor, who incarnated the
administrative bureaucracy which gave effect to the _Pax Romana_ and
the _Romana lex_ from the Euphrates to the Atlantic and from Scotland
to the Tropic of Cancer. Of all men Marcus Aurelius was the most
conscientious and the most sincere, and he understood, as perhaps no other
man in like position ever understood, the responsibility which impinged on
him, to allow no private prevention to impose an unfit emperor upon the
empire But Marcus had a son Commodus, who was nineteen when his father
died, and who had already developed traits which caused foreboding.
Nevertheless, Marcus associated Commodus with himself in the empire when
Commodus was fourteen and Commodus attained to absolute power when Marcus
died. Subsequently, Commodus became the epitome of all that was basest and
worst in a ruler. He was murdered by the treachery of Marcia, his favorite
concubine, and the Senate decreed that "his body should be dragged with a
hook into the stripping room of the gladiators, to satiate the public
fury." [Footnote: _Decline and Fall_, chap. iv.]