Commodus, the ruthless slayer of men and animals, was the son of Emperor Marcus Aurelius and his wife, Faustina the Younger. Adopted by Emperor Antoninus Pius (Faustina's father and his own uncle by marriage), Marcus Aurelius was groomed for ruling Rome at an early age. A prolific writer, his Meditations are still studied - and quoted - today:

• The happiness of your life depends on the quality of your thoughts
• Very little is needed to make a happy life. It is all within yourself, in your way of thinking.
• The first rule is to keep an untroubled spirit. The second is to look things in the face and know them for what they are.

By the time Marcus Aurelius became Emperor in 161, trade routes between Rome and her provinces had been established. But when Marcus Aurelius assumed sole power, the Empire's northern and eastern borders were not secure. (Follow this link to an animated map of Rome's expanding and shrinking territory throughout the centuries.) In 167, Rome's Emperor and his legions were fighting Germanic tribes along the Rhine-Danube frontier. At the time, Rome's army was mostly loyal to the Emperor.