Political map of Europe & the Mediterranean 23 January 41 AD (Reign of Caligula): When Tiberius died in 37 AD, the throne passed to his 24-year-old nephew Gaius Caesar, better known as Caligula. Despite his initial popularity, Caligula’s rule soon became arbitrary, cruel, and self-absorbed. He began pushing for his absolute power in Rome and, after abandoning Armenia (Mithridates of Armenia) and conducting a farcical military campaign against Germania and Britain, summarily executed the Client King of Mauretania (Ptolemy of Mauretania), provoking a revolt in Africa (Aedemon). In early 41 AD, resentful of Caligula’s behavior, the Praetorian Guard assassinated him and proclaimed his uncle Claudius the new emperor—a sinister first in the history of the Empire (Roman Empire).