Roman practice had a real problem with ruler worship. In the Greek east, honouring a living benefactor with a temple and a priest was ordinary civic behaviour and had been for centuries; at Rome it was the mark of a tyrant, and Julius Caesar's honours had been part of the case against him. Augustus's solution was to keep the two registers apart and to be seen doing it.
In the provinces he allowed the cities of Asia and Bithynia, as early as 29 BCE, to build temples to Roma and Augustus together, so that the emperor was never the sole object of the cult. In Italy and at Rome the object of worship was not the man but his genius, the guardian spirit that every Roman household head possessed, which was inserted into the shrines of the crossroads gods that the city's neighbourhoods already maintained. Oaths were sworn by his genius; libations were poured to it at private banquets by decree of the senate. The distinction was fine, and it was meant to be fine.
Death removed the difficulty. In September 14 CE the senate decreed his consecration, and a senator swore on oath that he had seen the emperor's form ascending to heaven from the pyre. A temple, a flamen and a college of priests followed, and Livia was appointed his priestess. What had been an awkward improvisation became a procedure: an emperor whose memory the senate approved became a god of the Roman state, and one it did not approve did not, so that the vote itself was the verdict on the reign.