There is an awesome moment in the opening chapter of the book of Luke where the writer frames his gospel as an epic celestial battle taking place in the heavenly realm: This is the story of the reign of men vs. the reign of God.
Luke makes it clear. What happened in these pages began in the days of King Herod of Judea (Luke 1:5). King Herod was a product and protector of empire. His father was appointed procurator of Judea by Julius Caesar. He subsequently appointed Herod military prefect of Galilee. After the death of Julius, Antony, and Octavian, Augustus Caesar favored Herod and gave him the name "king of the Jews," eventually becoming governor of Judea.
Herod was most concerned with maintaining his power — at all costs. He built the Roman Empire at his own people's expense. He built great monuments and structures, including the reconstruction of the Jerusalem Temple, enslaving his own people to do it. He used the Jews' labor to erect temples to pagan deities, and, paranoid of anyone who might usurp his power, Herod schemed against his own family, executing three of his own sons for insurrection — one only a few days before his death.
Enter a priest named Zechariah and his wife, Elizabeth.