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 (Principate) He raised his son Diadumenianus to be co-Emperor with him. Macrinus was praetorian prefect ("praefectus praetorio") under "Caracalla", whom he may have conspired to murder in April 217. His wife Nonia Celsa bore him a son, Diadumenianus, whom he made co-Emperor in 218; both were executed by partisans of "Elagabalus" (see below). The Severi, in addition to being the second dynasty "d'épée", are also the first Roman dynasty to have been restored to the purple. The restoration, however, brought with it a decidedly bizarre character: the first of the restored Severan Emperors, a Syrian historically known as "Elagabalus" (also seen