How did Augustus Caesar help unite the roman empire?

To help strengthen the Roman government, Augustus used a two pronged approach. First, he kept the important powers for himself as the "first citizen". By doing this he insured that he would have the necessary time to carry out his reforms, as opposed to the one year term limit imposed on the consuls. The second major prong of his approach was in the area of the military. To lessen the chance of another civil war disrupting the Pax Romana, Augustus had all the legions swear their oath of allegiance to him rather than to their commanders as had been done previously. This way an ambitious general would have a difficult time persuading his troops to march on Rome, as the Romans took oaths very seriously.