Marcus Aurelius Antoninus Augustus (often referred to as "the wise") was Emperor of the Roman Empire from 161 to his death in 180. He was the last of the "Five Good Emperors", and is also considered one of the more important Stoic philosophers. His two decades as emperor were marked by near continual warfare. He was faced with a series of invasions from German tribes, and by conflicts with the Parthian Empire in the east. His reign also had to deal with an internal revolt in the east, led by Avidius Cassius. Marcus Aurelius' work Meditations, written in Greek while on campaign between 170 and 180, is still revered as a literary monument to a government of service and duty and has been praised for its "exquisite accent and its infinite tenderness."