Incest of unequal gravity: the "incestus iuris gentium," which was applied to both Romans and non-Romans in the Empire, and the "incestus iuris civilis," which concerned only Roman citizens. Therefore, for example, an Egyptian could marry an aunt, but a Roman could not. Despite the act of incest being unacceptable within the Roman Empire, Roman Emperor Caligula is rumored to have had sexual relationships with all three of his sisters (Julia Livilla, Drusilla, and Agrippina the Younger). Emperor Claudius, after executing his previous wife, married his brother's daughter Agrippina the Younger, and changed the law to allow an otherwise illegal union.
Agrippina the Elder Agrippina the Elder Agrippina the Elder (Latin:"Vipsania Agrippina"; Classical Latin: , c. 14 BC – AD 33), commonly referred to as "Agrippina the Elder" (Latin: "Agrippina Maior"), was a prominent member of the Julio-Claudian dynasty. She was born in c. 14 BC the daughter of Marcus Vipsanius Agrippa, a close supporter of Rome's first emperor Augustus, and Augustus' daughter Julia the Elder. At the time of her birth, her brothers Lucius and Gaius were the adoptive sons of Augustus and were his heirs until their deaths in AD 2 and 4, respectively. Following their deaths, her cousin Germanicus was made