Claudius (25 January 41CE - 13 October 54CE). Tiberius Claudius Drusus was the younger son of Nero Claudius Drusus (brother of Tiberius) and Antonia (daughter of Mark Antony). He was thought to be mentally retarded because he suffered some form of paralysis, but in actuality, was a competent ruler. Claudius had his third wife, Valeria Messallina, executed in 48CE, and married his niece Agrippina Jr. He adopted Agrippina's son, Nero, and named him his heir, disinheriting his own son, Britannicus, probably because of his mother's disgrace.