The Divine Augustus was a mild ruler [princeps], if someone should judge him beginning from the inception of the Principate... in his youth, however, he had a hot temper, his rage burnt bright, and he did many things which he used to look back upon in later age with pain.
For ten years he [i.e. Octavian] administered the Triumvirate that had been established with a view to reconstituting the Republic. While holding this position, he resisted his colleagues for some time, opposing the idea of carrying out a proscription ["legal murder"]. But once that policy had been adopted, he implemented it with more severity than either of the other two. [other sources claim 300 senators and 2000 equestrians were on the list of the proscribed]
Nor was he moderate in victory [i.e., after the battle at Philippi], but, having sent the head of Brutus to Rome to be thrown at the foot of Caesar's statue, he vented his rage savagely against all the most distinguished of his captives, not omitting verbal abuse. For example: when one man humbly begged to be granted due burial, he is said to have replied that the birds would be given charge of that matter quite soon. When others, a father and son, begged for their lives, he is said to have ordered them to draw lots or to play at even and odds in order that one might be granted the privilege of living; and he is said to have looked on when, the father having offered himself in his son's place and having been slain, the son, too, killed himself of his own accord.
When Perusia had been captured he [i.e. Octavian] punished many, answering those who tried to beg for mercy or who sought to make excuses for their actions with one phrase: "Moriendum est." ["It is time to die."] Certain authorities record that three hundred men of both orders were selected from those who had surrendered without condition and, on the Ides of March, were slaughtered like cattle before an altar set up to the Divine Julius.
The political dominance of Pompey and Crassus quickly passed to Julius Caesar, as did the armies of Lepidus and Antony to Augustus, who, under the name of princeps, took under his control the entire Roman state, worn out as it was by civil strife. ... [2] After there were no longer any public armies in the field (Brutus and Cassius having been slaughtered and Sextus Pompeius having been crushed in Spain) and with no other leader remaining even for the Julian party, with the exception of Octavian (Lepidus being out of the way and Antony having been killed), the latter doffed the name of triumvir and put on that of consul, and, "content" with his tribunician powers for "the assurance of the safety of the plebs," he seduced the army with gifts, the general populace with free grain, and everyone with the lure of peace and leisure after the toils and stresses of civil war. Gradually he began to increase his power, taking to himself the functions of the Senate, of the magistrates, and of the laws. No one opposed him: his fiercest enemies had died, either in battle or in the ensuing proscriptions, while the rest of the nobiles were rewarded with riches and offices in direct proportion to their readiness to display a fawning servility.