How did governance change in ancient Rome?

At first, a single ruler, the king, ruled for a long time. However, at that time there was already a council of elders and a Senate that replaced it. This period of tyranny, as it is called in history by the Romans, ended with the establishment of a republic. Which, over the course of about two centuries, gradually outlived its usefulness. And starting from the 30th year, Octavian Augustus, who became the first emperor of Rome, came to power. After the empire was gradually modernized, the institution of dual power (two halves of empires) was introduced, and then – 4-power (where there are two emperors and two of their successors).