Octavia (69 - 11 B.C.) was the sister of Augustus Caesar and wife of Claudius Marcellus (three children)), then of Mark Antony (two daughters).
Octavia's second daughter by Marcellus married Agrippa. Their son married Julia, Augustus Caesar's daughter, and Caligula was that couple's grandson on his mother's side (his father being Germanicus, brother of Claudius).
When Antony announced he was married to Cleopatra VII of Egypt and that her son Caesarion was the legitimate heir of Julius Caesar and Augustus Caesar therefore a usurper, Augustus ordered his sister to leave Antony's house and return to his. Octavia was a remarkable woman who reared several of Antony's children by his other wives.
Octavia (d. 62 A.D.) was the daughter of Claudius and Messalina and the first wife of her step-brother Nero.