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
Roman emperor he turned down supreme authority in exchange for a collection of various powers and offices, which in itself was a demonstration of his "auctoritas" ("authority"). As holding "princeps senatus", the emperor declared the opening and closure of each Senate session, declared the Senate's agenda, imposed rules and regulation for the Senate to follow, and met with foreign ambassadors in the name of the Senate. Being "pontifex maximus" made the emperor the chief administrator of religious affairs, granting him the power to conduct all religious ceremonies, consecrate temples, control the Roman calendar (adding or removing days as needed), appoint the vestal