Iullus Antonius also. Through his half-sister Antonia Minor, he was a maternal uncle of Germanicus, Livilla and the Emperor Claudius. Lastly, he was a paternal great-uncle of the Emperor Caligula, Julia's grandson by Agrippa, and the Empress Agrippina the Younger, Julia's eldest granddaughter, and Claudius' niece and fourth wife, as well as other children fathered by Germanicus and his wife Agrippina the Elder: Nero Julius Caesar, Drusus Caesar, Julia Drusilla, and Julia Livilla. Through Agrippina the Younger, Iullus was a maternal great-great-uncle of the Emperor Nero. Through his half-sister Antonia Major and stepsister Claudia Marcella Minor, he was also great-uncle to Claudius'
Agrippina the Younger cousin, Drusilla's widower Marcus Aemilius Lepidus, were involved in a failed plot to murder Caligula, a plot known as the "Plot of the Three Daggers", which was to make Lepidus the new emperor. Lepidus, Agrippina and Livilla were accused of being lovers. Not much is known concerning this plot and the reasons behind it. At the trial of Lepidus, Caligula felt no compunction about denouncing them as adulteresses, producing handwritten letters discussing how they were going to kill him. Lepidus was executed. Agrippina and Livilla were exiled by their brother to the Pontine Islands. Caligula sold their furniture, jewellery, slaves