Herod the Great is one of the most important characters in Jewish history. He was ambitious, cruel and paranoid to be sure, but, nevertheless, he remains a very significant person in the terms of understanding the period of Roman domination of the Jewish people.
Herod first leadership role was as governor of the Galilee, a position granted to him by his father, Antipater. Early on in his career he demonstrates his brutality by ruthlessly crushing a revolt in the Galilee.
The background to Herod's rise to power is the Roman civil war that will transform Rome from a republic into and empire ruled by the Caesars or emperors. In 44BCE Julius Caesar is murdered by Brutus and Cassius who are in turn defeated by Anthony and Octavian in 42 BCE. The Battle of Actium in 31 BCE is the final showdown between Octaviun and Anthony. Octaviun emerged as the unrivaled victor, changing his name to Augustus and becoming the first Roman emperor. Herod had originally sided with Anthony but switches allegiance at the last minute and backs Octavian. His last minute support for Octavian earns him Augustus's confirmation as King of Israel.
Herod reigned as king of Judea from 37 BCE until his death in 4 BCE, a very long reign of 33 years, and in many ways a good period in terms of development of the country and social stability. Part of the reason for the stability was that during this time, the Romans took a backseat role in the day-to-day life of the Jews.