The Antonine plague--the world's first pandemic--did not find the Roman Empire at its strongest. In fact, climate change was affecting some key regions of the Roman Empire decades prior to the Pax Romana's end. The food supply of the empire was in jeopardy, weakening the population and encouraging migration into already crowded Roman cities. What went wrong and why?

In the mid AD 160s, it looked like Rome was winning. The war in Parthia was going well. The two emperors, Marcus Aurelius and Lucius Verus, were well supported. But then a sudden and mysterious disease ripped across the Empire and into Italy. The outbreak was one of several jarring events that shook the Roman world.

As far as we know, Marcus Aurelius grew up in a period of general peace and tranquility. But so did his adoptive brother, Lucius Verus. When the emperor Antoninus Pius died, both men--Marcus and Lucius--had claims to the empire. But could Rome really function with two emperors? The Roman Senate thought Marcus alone should rule. Adding to the awkwardness of the transition, the Parthian empire attacked Rome's client state Armenia. An all out war would follow; but first the Romans needed to resolve their leadership situation.

Antoninus Pius was apparently a great emperor, but we know very little details about his reign. Instead, he is remembered as the emperor who prepared the way for his successor, Marcus Aurelius--one of the most famous emperors in all of Roman history. But Hadrian had put in place two successors, not one, for Antonine Pius. How did Antoninus balance his obvious preferences for Marcus Aurelius while also honoring the wishes of Hadrian?

Antoninus Pius (138-161 AD) ruled peacefully, leaving a lesser-known legacy. What can we know about this often neglected emperor? His coins illuminate some of the story. Gold coins showcase his loyalty: to the Senate, to Hadrian, and to his wife Faustina. Silver coins highlight his concern for the people's well-being, especially the grain supply.

Was the Roman military the well-oiled machine portrayed in many films and works of historical fiction? Today we conclude this short series on the Roman military by looking at discipline. We’ll explore soldiers’ training regimen, from physical conditioning to mock battles. Roman soldiers took strict oaths, endured harsh punishments and sometimes won valuable rewards. But there are plenty of sources that suggest a military plagued by corruption, laziness and even cowardice. So what should we believe? The Pax Romana seems like the peak of Roman power, but was this because of the Roman military, or in spite of it?

Why was the Roman military so powerful? How did its structure work? What men joined up and what did they actually do with their time? Twenty-five years was a long time to serve. Interestingly, the Roman military offered credible opportunities to advance in Roman society. And for non-Romans, military service could get them on the path to becoming citizens themselves.

Here is the first of several episodes on the Roman military. How did the military fuel expansion, secure borders and bolster the emperor's power? How large was the military and what did it cost? What role did soldiers play in both receiving imperial ideology, as well as advancing it?

The Pax Romana may have thrived, but much of its prosperity was born on the backs of million. On this episode, we look at a darker side of the Pax Romana, and the institution of Roman slavery. How did it function--from the brutal realities of capture and sale--to the opportunities for freedom? Roman slavery was of questionable economic benefit, so why did Romans keep this institution around for so long?

Roman society was highly stratified. Rank, wealth, birth and political power--not necessarily merit--determined one's place in the world. The social system was intricated and divided; both masses and elites were subdivided in a variety of ways. And above all was the emperor. He reigned supreme, as not just a ruler, but a patron and father over the entire Roman world.