One gained it through money and another was found hiding behind a curtain.
For centuries, becoming emperor of the Roman Empire was an enticing prospect, and numerous people schemed, battled and murdered each other for this ultimate prize. But being the ruler of ancient Rome was a risky business, despite the immense wealth it brought and the almost unlimited authority over powerful armies and a vast territory.
Probably the most famous emperor to inherit the throne was the fifth Roman emperor, Nero, who was born Lucius Domitius Ahenobarbus in A.D. 37. His mother, Julia Agrippina, a great-granddaughter of Augustus, became the fourth wife of the emperor Claudius in A.D. 49 and persuaded her new husband to adopt the boy later that year. Nero then inherited the imperial throne at age 17 after Claudius died in A.D.
Caligula, a great-grandson of Augustus who reigned from A.D. 37, was initially popular, but stories of his predilections for sadism and sexual perversion have led him to be portrayed as a brutal and lascivious tyrant. Eventually he alienated both the Roman nobility and the army, and Caligula was assassinated by officers of the Praetorian Guard in A.D. 41.
Didius Julianus was next on the throne. He'd served as governor of several provinces and was immensely wealthy. According to the second-century Roman historian Cassius Dio, the Praetorians announced after killing Pertinax that they would sell the throne to the man who paid the highest price, and Julianus won the subsequent bidding war by offering 25,000 sesterces to every Praetorian soldier — the equivalent of several years' pay.
Historian William Broadhead at the Massachusetts Institute of Technology in Cambridge noted in an email to Live Science that the Roman Empire was a military autocracy."The emperor's legitimacy was based on his command of the very powerful Praetorian Guard at Rome and of the majority of the legions stationed in the provinces," he said."Those two military institutions learned soon enough that they could play the role of kingmaker.