Marcus Aurelius was born in Rome in 121. In 138 the future emperor Antoninus Pius, named as Hadrian’s successor, adopted him, which put him in line for the throne. He was taught Latin by Fronto, and of his teachers in philosophy Junius Rusticus did most to turn him toward Stoicism. He ruled from 161 until his death in 180, at first jointly with his adoptive brother Lucius Verus.
His reign was hard. The Antonine Plague, which broke out in 165 or 166, killed an estimated five to ten million people, and he spent years at war with the Marcomanni, Quadi and Iazyges across the Danube. Through it he kept the private notes, written in Greek, that we now call the Meditations, a key source for ancient Stoic thought.