Herod was born in 73BC and died in 4BC. Although a practising Jew he was of Arab descent by both father and mother. His father was Antipater, an Edomite, who supported Pompey when he invaded Palestine and thus began a long and beneficial association with Rome.
Julius Caesar conferred Roman citizenship upon Antipater and made him procurator of Judea in 47BC. This citizenship would continue for his family and his father made Herod governor of Galilee in 48BC. Herod became a lifelong friend of Mark Antony, who then made him tetrarch of Galilee.
In 40BC, when civil war broke out after the Parthian invasion, Herod fled to Rome. The senate in Rome made him King of Judea and gave him an army to enforce his claim. In 37BC he became undisputed leader of Judea and maintained his position for the next 32 years.
He divorced his first wife and married Mariamne, a Hasmonean princess. The union was political but he did indeed love Mariamne.
During the conflict between Julius Caesar's heirs, Octavian and Mark Anthony, Herod supported his friend, even when Cleopatra seized some of his land. After Octavian won the conflict, Herod submitted to Octavian, admitting his position during the war. Octavian had met Herod in Rome and knew he was the ruler for Palestine and so confirmed him in his kingship, and restored his lands.
Augustus (Octavian) twice increased Herod's lands, till they came to include parts of what is now Jordan to the east, and southern Lebanon and Syria.
Herod built massive fortresses and cities. One of his best known building projects was the rebuilding of the Temple in Jerusalem.
There was also a dark side to Herod, which became more obvious as he grew older. This was fed by his own family's intrigues. His sister Salome continually poisoned his mind against his beloved wife Mariamne (ably assisted by Mariamne's own mother). Herod eventually murdered not only Mariamne, but also her sons, brother, grandfather and mother.
Herod suffered much physically and mentally in his later years and also lost the favour of Augustus. The slaying of the children in Bethlehem not long after the birth of Christ was consistent with his state of mind at this time.
After his death his kingdom was divided between his three sons, Archelaus, Philip and Antipas.