Fronto married his cousin Faustina the Younger and fought the Marcomannic Wars.
This emperor's reign saw a Parthian invasion of Syria that caused a plague spread by returning troops. A Germanic horde besieged Aquilea after this man crossed the Danube on a punitive expedition. This student of the tutor Fronto married his cousin Faustina the Younger and fought the Marcomannic Wars. After a long period of apprenticeship under his predecessor Antoninus Pius, this man became co-emperor in 161 along with Lucius Verus. For 10 points, name this Roman emperor best known for his exploration of Stoic philosophy, the Meditations.
This emperor's reign saw a Parthian invasion of Syria that caused a plague spread by returning troops.
Marcus Aurelius [prompt on partial answer; or Marcus Aurelius Antoninus Augustus]