Atia Balba Caesonia (85 BC – 43 BC), sometimes referred to as Atia Balba Secunda to differentiate her from her two sisters, was a Roman noblewoman. She was the daughter of Julius Caesar's sister Julia Caesaris, mother of the Emperor Augustus, step-grandmother of the Emperor Tiberius, great-grandmother of the Emperor Claudius, great-great grandmother of the Emperor Caligula and Empress Agrippina the Younger, and great-great-great-grandmother of the Emperor Nero. The name Atia Balba was also borne by the other two daughters of Julia Caesaris and her husband praetor Marcus Atius Balbus. They were Atia’s older sister Atia Balba Prima, and her younger sister was Atia Balba Tertia. In former portrayals of the ancient history the mother of Augustus, Atia, was still described as the elder one from two sisters.