I, Claudius by Robert Graves

Below is the book description:

Tiberius Claudius Drusus Nero Germanicus lived from 10 B.C. to 54 A.D. Despised as a weakling and dismissed as an idiot because of his physical infirmities, Claudius survived the intrigues and poisonings that marked the reigns of Augustus, Tiberius, and the mad Caligula to become emperor of Rome in 41 A.D. The first part of Robert Graves’s two-part account of the life of Tiberius Claudius, I, Claudius stands as a landmark historical novel of the 20th century from one of its great writers.