Galatians 4:4 But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law
What a simple verse, yet how full of meaning for a life of faith.
Think what the fulness of time implied.
Jesus, Light of the world, had to be conceived at Hanukkah.
He had to be born at Sukkot (not Christmas, which was adopted as the Nativity to fit in with pagan customs).
John Baptist had to be born on the day of Pesach (Passover), fitting for one who would announce Jesus as the Lamb of God.
Jesus had to be born in Bethlehem. But Mary and Joseph lived at Nazareth.
No caring husband would force his pregnant wife to travel all the way from Nazareth to Bethlehem when she was in advanced pregnancy.
So God moved the heart of Caesar to decide on a census of all Jews in the Empire, and issue a decree that every male Jew had to register himself in the city of his ancestors. This compelled Joseph to take Mary to Bethlehem so the prophecy could be fulfilled. It also forced the place of birth to be a stable as there were too many people in Bethlehem for the census, and there was no room for Joseph and Mary in the inn. Jesus had to be born at night, so the angels could appear in an angelic manifestation against the bakcdrop of a night sky.
Before He could move the heart of this Caesar, there had to be a Caesar in place as Emperor over Palestine. But before Rome, the Greeks were the rulers, and they tried their best to spread Greek culture, destroy the Jewish religion, and desecrate theTemple, in which Jesus would be presented in the Temple 40 days after His birth. But the Judah under the leadership of the Maccabees, defeated the Greeks, and rededicated the Temple, thus fufilling the prophecy of Zecharias
Zechariah 9:13 When I have bent Judah for me, filled the bow with Ephraim, and raised up thy sons, O Zion, against thy sons, O Greece, and made thee (Zion) as the sword of a mighty man.
And before that there were a whole lot of prophecies that had to be fulfilled in the fulness of time. The Jews had to returned from exile after 70 years (fulfilling he prophecy of Jeremiah), the order to return was given by Cyrus (prophecied by Isaiah). Cyrus was a Persian, (the breastplate of silver of Nebuchadnezzar's dream in the book of Daniel), Persia had to be conquered by Greece (thighs of brass), and finally Greece by Rome (legs of iron), and then in the fullness of time with Rome ruling over Palestine, the census ordered by the Roman Caesar could take place..
All of the above show the amazing sovereignty and power of God. For the Heavens do rule!
The year of Jesus' birth was planned so He could start His public ministry at 30 years, and have enough time (3 years) for teaching ministry and demonstration of His divine Sonship, before finally entering Jerusalem on the precise date foretold by the prophet Daniel, so He could fulfill all the prophetic symbolism of the preparation of the Passover Lamb.
In God's perfect timing, all these things were taken into account and in the fullness of time, God sent forth His Son, to be born under the Law, at a time when the Greek language was in full flower for the dissemination of the gospel throughout the Roman empire, and the Romans were in control so Jesus could be crucified, fulfilling Psalm 22, and the Roman roads were all in place so Peter could travel to Caesarea to open up the door for Gentiles to be baptized and so Paul could carry the gospel on horseback, and in chariots and by ship, all across the Roman world.