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I, Claudius (1934) is a novel by English writer Robert Graves, written in the form of an autobiography of the Roman Emperor Claudius. Accordingly, it includes the history of the Julio-Claudian Dynasty and the Roman Empire, from Julius Caesar's assassination in 44 BC to Caligula's assassination in 41 AD. The 'autobiography' of Claudius continues (from Claudius' accession after Caligula's death, to his own death in 54) in Claudius the God (1935). The sequel also includes a section written as a biography of Herod Agrippa, contemporary of Claudius and future King of the Jews.

The story begins with an apology by Claudius for having ended his first history on a dramatic point, and continues with a brief history of his friend Herod Agrippa. Herod Agrippa was a schoolmate of Claudius and was liked by Claudius' mother Antonia. Herod always finds himself in debts and danger in the East and in Rome. He eventually gains the favour of Caligula and is made King of Bashan. Herod is in Rome when the assassination of Caligula happens and quickly is able to convince Claudius to accept being Emperor to avoid Civil War.  Claudius reluctantly executes Cassius Chaerea and several of the assassins and begins tirelessly working for the sake of Rome. He applies himself to the law courts, and demonstrates his intelligence in being able to locate one of Augustus' lost Eagles. Claudius also begins work on building a harbour in Ostia to help preserve the Romans' food supply. Claudius is also able to quell two major mutinies against him and has a successful conquest of Britain.  During this time Herod Agrippa conspires to take over the East as he regards himself as the Messiah. When he announces himself as such he breaks the first commandment by declaring himself as a god. Herod quickly dies a painful death, just as his grandfather had died, but he dies imploring Claudius to forgive him and not to trust anyone.  Throughout Claudius' reign he is being unwittingly manipulated by his adulterous wife Messalina who kills many of her enemies as well as being involved in bribery. She eventually conspires to usurp the monarchy with her lover Gaius Silius. Claudius is distraught and crushed by such news and is given an "Olympian Mixture" in order to manage through the ordeal. Claudius arrests Silius and the leaders of the coup. Messalina is executed without Claudius's consent, and Claudius has no reaction during his "Olympian" state, and even bemusedly jokes about being worshipped as a god in Britain.  However, upon being relieved of the "Olympian Mixture" Claudius is crushed. Now deploring his actions Claudius decides that the only way the Republic can be restored is by having a true mad monarch rather than the reign of a benevolent one. Comparing himself to the fable of the frogs who desired a King, Claudius privately refers to himself as "Old King Log" and plays a weak and easily manipulated fool. He then incestuously marries his niece Agrippinilla whom he openly despises. In feeble old age Claudius now excessively enjoys gladiatorial games and frequently is intoxicated and makes himself oblivious to Agrippinilla's schemes to gain power and make her son Nero Emperor. Claudius, foreseeing that Nero will be a terrible ruler, plans on having his son Britannicus removed to live with the Northern Britons and later to return as Rome's saviour. But Britannicus refuses to do such, and admits that while he loves the Republic, the Republic is dead and he wants to challenge Nero for the right to rule Rome as an Emperor. Crushed, Claudius agrees, knowing that he is sending his son to his death. Claudius resignedly accepts that his death will be soon with numerous signs suggesting such.
I, Claudius