Upon his adoption, Octavius assumed his great-uncle's name Gaius Julius Caesar. Roman citizens adopted into a new family usually retained their old nomen in cognomen form (e.g., "Octavianus" for one who had been an Octavius, "Aemilianus" for one who had been an Aemilius, etc.). However, though some of his contemporaries did, there is no evidence that Octavius ever himself officially used the name "Octavianus", as it would have made his modest origins too obvious. Historians usually refer to the new Caesar as "Octavian" during the time between his adoption and his assumption of the name Augustus in 27 BC in order to avoid confusing the dead dictator with his heir.