Each year, the citizens chose a few government officials from a group called the Senate. The idea was to prevent anyone from having too much power.
Julius Caesar, a general, had many military successes, which helped him gain power in the Republic. In 49 BC, Caesar marched his army to Rome and seized power. A civil war followed, in which Caesar defeated his enemies and became ruler of Rome.
This one-man rule worried some senators, and the senators murdered Caesar. Caesar's death brought a new civil war and the collapse of the Republic. Caesar's son Octavian gained control and brought peace to Rome. Octavian was renamed Augustus and became the first of Rome's emperors.