History of the Roman Empire from this point on, leading his biographers to label him as insane. Most of what history remembers of Caligula comes from Suetonius, in his book "Lives of the Twelve Caesars". According to Suetonius, Caligula once planned to appoint his favourite horse Incitatus to the Roman Senate. He ordered his soldiers to invade Britain to fight the Sea God Neptune, but changed his mind at the last minute and had them pick sea shells on the northern end of France instead. It is believed he carried on incestuous relations with his three sisters: Julia Livilla, Drusilla and Agrippina the Younger. He
Holy Roman Emperor of Eastern Francia fell within the boundaries of the Holy Roman Empire. The various German princes elected one of their peers as "King of the Germans", after which he would be crowned as emperor by the Pope. After Charles V's coronation, all succeeding emperors were called "elected Emperor" due to the lack of papal coronation, but for all practical purposes, they were simply called "emperors". The term "sacrum" (i.e., "holy") in connection with the German Roman Empire was first used in 1157 under Frederick I Barbarossa. Charles V was the last Holy Roman Emperor to be crowned by the Pope