The emperor Marcus Aelius Aurelius Antoninus who reigned from 161-160 was the only Roman emperor besides Julius Caesar whose writings were to become part of the canon of Western classics. His Meditations are a loosely-organized set of thoughts relating to the stoic philosophy which had been popular among the better-educated citizens of Rome for some centuries. It stressed self-discipline, virtue, and inner tranquillity. Aurelius was also a social reformer who worked for the improvement of the lot of the poor, slaves, and convicted criminals.