Marcus Aurelius

Ruled Rome from 161 to 180 and spent most of it at war, on the Danube frontier, dealing with plague and an attempted usurpation by a trusted general.

He had been trained in Stoic philosophy from adolescence and kept a private notebook in Greek that was never meant to be published. It survived anyway. Meditations is the result: not a system, but the same man reminding himself of the same handful of things.

He is often held up as the philosopher king. He also continued the persecution of Christians and chose his son Commodus as successor, which went badly for everyone. Both belong in the picture.