Antoninus Pius, Marcus Aurelius\u2019 adopted father and predecessor, was not a Stoic. He didn\u2019t identify as, nor did anyone call him, a philosopher. He left behind no writings. There are no anecdotes of him dropping in on lectures in Greece or studying under some guru.And yet, of all the people in Marcus\u2019 life, Antoninus was the most Stoic. He was cool under pressure. He quietly went about his business. He was hard-working, self-sufficient, and never got worked up. He was a beloved leader. His me...