"Claudia Antonia (Classical Latin: ANTONIA•CLAUDII•CAESARIS•FILIA) (c. AD 30–AD 66) was the daughter and oldest surviving child of the Roman Emperor Claudius and the only child of ...
his second wife Aelia Paetina. Antonia was a great great-niece of the Emperor Augustus, great-niece of the Emperor Tiberius, first cousin of the Emperor Caligula, half-sister to Claudia Octavia and Britannicus (her father´s children by his third marriage to Valeria Messalina), and cousin, stepsister and sister-in-law of the Emperor Nero." - (en.wikipedia.org 30.10.2019)
