How the Roman Republic became the Roman Empire

Could you tell us how Rome went from a republic to an empire? How did that happen, roughly? In the ancient world, it was common to attack a city, take what was valuable, including people as slaves, and destroy the place. This practice certainly continued, but more often a conquered city would be added to the victor's territory. The Assyrians of Mesopotamia were masters of this long before Rome. The Romans conquered all the other tribes in Italy and then defeated the Etruscans who had been the major power. Instead of destroying their cities, the Romans made these people citizens, allowed them to live just as they had done before, but required them to live under Roman law, pay taxes, and provide men for the army. As their army grew, the Romans took territories outside of Italy, like the island of Sicily. Part of Sicily was claimed by another city-state, Carthage of North Africa. And when two Sicilian kingdoms went to war, Carthage was on one side, and Rome on the other. This led to the Punic Wars between Carthage and Rome, starting in 264 BC and ending in 146 BCE. This major war began as a small dispute between kings, but it changed the entire balance of power in the Mediterranean. Before the war, Carthage was the superpower, and Rome was just a little port city. After the war, Carthage was defeated and subject to Rome, while Rome became the supreme power. When the wars were over, Rome held territories from Italy through North Africa, Greece, and Spain, and continued to grow, adding modern-day Turkey, France, and parts of Germany. The Roman Republic grew, but the government's structure remained the same. In 60 BCE, three powerful men, Julius Caesar, Marcus Crassus, and Gnaeus Pompey formed an alliance known as the First Triumvirate, and managed to hold absolute power until 53 BCE, when Crassus was killed in battle of the Parthians, and Caesar and Pompey then turned on each other and went to war. Pompey was killed, and Caesar declared himself dictator for life, with absolute power over Rome. The office of dictator had long been legal. The Senate could appoint someone a dictator in times of crisis, and had done so in the past. But once that crisis was over, the person stepped down. The classic example of this is Cincinnatus, a statesman who was elevated to dictator to rescue one of Rome's armies, which was trapped by an enemy tribe in 458 BCE. After he saved the army, when the crisis was passed, Cincinnatus willingly surrendered power and returned to his former life. No one had ever declared themselves dictator before, much less dictator for life. Some of the senators feared Caesar would next declare himself king, and so they assassinated him. Caesar's nephew, Octavian Caesar, and Caesar's friend and second-in-command, Mark Antony, hunted down and killed the assassins, but they soon went to war with each other. Antony allied himself with Cleopatra VII in Egypt, and had a strong and efficient army, but Octavian's forces defeated them both at the Battle of Actium in 31 BCE. Octavian was then hailed by the Senate as the savior of Rome. Many scholars today believe that Octavian used Actium as a propaganda tool to gain more power, and they're probably right. Octavian often depicted Antony and Cleopatra as greater dangers to Rome than they really were. After his victory, the Senate gave Octavian the honorary title of Augustus, meaning the illustrious one, the great one basically. Less than ten years after Actium, Augustus Caesar was given supreme power over Rome and became its first emperor. Augustus then reformed the government so that the person who became emperor, who was chosen by the Senate, held the position for life. He also enlarged the army, the legions of Rome, and expanded its territories into Egypt and Mesopotamia. And so began the Roman Empire, which lasted in the west from 27 BCE to circa 476 CE, and in the east from 330 CE to 1453 CE.