Octavian was named Augustus on 16 January 27 BC

Octavian was given the name Augustus by decree of the Roman Senate on 16 January 27 BC, the date usually taken as the start of the Roman Empire. No law, crown or title of “emperor” was involved. The decree capped a carefully staged settlement that had begun three days earlier, on 13 January, when Octavian announced he was handing his extraordinary powers back to the Senate and people. That was four years after his victory at Actium had left him without a rival.

The senators, as expected, insisted he stay. After a show of reluctance he accepted a huge province made up of most of Spain, Gaul, Syria, Cyprus and Egypt for ten years, governing it through his own deputies. The rest of the empire stayed with governors chosen by the Senate. In practice the arrangement rested on the army, which he reorganised from about 60 legions after the civil wars down to 28, each sworn to him personally.

The name was chosen to impress without alarming anyone. Augustus carried religious overtones (it echoes augur) and suggested personal standing (auctoritas), not kingship. Rome had loathed kings since expelling its last one. He ruled as princeps, “first citizen”, for about four decades until his death in AD 14.

What Augustus said he did

Near the end of his life Augustus wrote his own account of his career, the Res Gestae. He describes January 27 BC like a lawyer:

“I transferred the republic from my own control to the will of the senate and the Roman people.” (Augustus, Res Gestae 34)

He adds that the Senate hung laurels on his doorposts and placed a golden shield in the Senate house in his honour. From then on, he claims, he outranked everyone in prestige but held no more formal power than his fellow magistrates. Historians read that line as the founding fiction of the principate: a monarchy presented as a restored republic. The same fiction made succession awkward, because a man with no special powers had no right to name an heir.