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
Matthias, Holy Roman Emperor Matthias's brother Archduke Maximilian, who hoped to secure the succession for the inflexible Catholic Archduke Ferdinand (later Emperor Ferdinand II). The start of the Bohemian Protestant revolt in 1618 provoked Maximilian to imprison Klesl and revise his policies. Matthias, old and ailing, was unable to prevent a takeover by Maximilian's faction. Ferdinand, who had already been crowned King of Bohemia (1617) and of Hungary (1618), succeeded Matthias as Holy Roman Emperor. Names in other languages: "Matthias, by the grace of God elected Holy Roman Emperor, forever August, King in Germany, of Hungary, Bohemia, Dalmatia, Croatia, Slavonia, Rama, Serbia, Galicia, Lodomeria,