How do you run one of the largest empires in history, spanning thousands of miles, dozens of languages, and too many skin colors and cultures to count? Put a celebrity in charge. True, the Romans may not have had Rolling Stone covers or Oprah interviews , but they were the original publicity gurus. Before the Roman Empire came to be in the first century B.C., Rome itself was the picture of civil disorder. After the dictator Gaius Julius Caesar was assassinated, factions duked it out for dominance, causing financial upheaval, violence, strife and partisan politics that would make even today’s Congress blush. To Roman oracles, the explanation was simple: The gods must be angry. The solution? Create new gods. Augustus Caesar, the adopted son of Julius Caesar and the Roman Empire’s first emperor, was a natural at public relations. To appease the people and avoid the same bloody end as his father, he called...