How Were Julius Caesar and His Successor, Augustus, Related?

Augustus Caesar was the first true Roman Emperor

Octavian-Augustus strikes a pose. Wikimedia Commons Public Domain

Augustus was Julius Caesar's great-nephew whom he adopted as his son and heir. Born Gaius Octavius on September 23, 63 B.C., the future Augustus was the son of Octavius, a relatively average praetor from Velitrae, and Atia, the daughter of Julius Caesar's sister Julia.

Why Did Julius Caesar Adopt Gaius Octavius (Octavian)?

Julius Caesar had no son, but he did have a daughter, Julia. Married several times, including to Caesar's longtime rival and friend Pompey, Julia sadly died in childbirth in 54 B.C. This ended her father's hopes for an heir of his own direct blood (and incidentally ended the possibility of a truce with Pompey). 

So, as was common in ancient Rome then and later, Caesar sought his closest male relative to adopt as his own son. In this case, the lad in question was young Gaius Octavius, whom Caesar took under his own wing in the final years of his life. When Caesar went to Spain to fight the Pompeians in 45 B.C., Gaius Octavius went with him. Caesar, arranging the schedule in advance, named Gaius Octavius Master of the Horse for 43 or 42 B.C. Caesar died in 44 B.C. and in his will adopted Gaius Octavius. Octavius took the name Julius Caesar Octavianus at this point, thanks to the encouragement of Caesar's own veterans.

How Did Octavian Become Emperor?

By taking his great-uncle's name, Octavian also assumed Caesar's political mantle at the age of 18. While Julius Caesar was, in fact, a great leader, general, and dictator, he was not an emperor. In fact, he was in the process of instituting major political reforms when he was assassinated by Brutus and other members of the Roman Senate.

While Octavian had the support of the Senate, he was not immediately made dictator or emperor. It took several years to consolidate his position, as Julius Caesar's assassination led to an assumption of power by Marcus Antonius (better known to modernity as Marc Antony) and his beloved Cleopatra VII. Octavian and Marc Antony battled for control of Rome and the legacy Caesar left behind. Antony and Octavian ultimately decided the fate of Rome at the Battle of Actium in 31 B.C. Antony and his lady love Cleopatra both committed suicide after Octavian emerged victorious. 

It took many more years for Octavian to establish himself both as emperor and as the head of the Roman religion. The process was complex, requiring both political and military finesse.

Augustus Caesar's Legacy

A savvy politician, Octavian had even more of an impact on the history of the Roman Empire than did Julius. It was Octavian who, with Cleopatra's treasure, was able to establish himself as emperor, effectively ending the Roman Republic. It was Octavian, under the name Augustus, who built the Roman Empire into a mighty military and political machine, laying the groundwork for the 200-year Pax Romana (Roman Peace). The Empire as founded by Augustus lasted for almost 1,500 years.