Mary and Joseph register for the census before Governor Quirinius. Byzantine mosaic c. 1315
In those days a decree went out from Caesar Augustus that all the world should be registered. This was the first registration when Quirinius was governor of Syria. And all went to be registered, each to his own town. And Joseph also went up from Galilee, from the town of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David, to be registered with Mary, his betrothed, who was with child. (Luke 2:1-5).
Two things are certain in this life: death and taxes, said Benjamin Franklin. The Roman Empire was no exception, excelling in both.
They had to. The Roman Empire was vast. At the time of Jesus birth, Octavian, later called Caesar Augustus, had been emperor since 31 BC, and he was a canny king. He didn't call himself king, emperor or dictator, though in fact he was. He was able to assume total power without alienating the Senate and to continue the fiction that the Republic was a Republic resting on a constitutional monarchy.
The Empire had grown since its founding in 510 BC when Rome overthrew its rulers to the north and west, the Etruscans. (It's where we get the word Tuscany). Octavian had to defend current borders, enlarge its borders, quell uprisings, sustain the Court, distribute free grain to local families each month, pay its vast army...and it did it through taxing the people. Just the grain distribution to locals alone took all of conquered northern Africa's produce for the year.
The heavy taxes did however, also pay for the many amazing civic infrastructure improvements throughout the empire. Aqueducts brought water. Paved roads allowed for trade and commerce (as well as military movement). Amphitheaters allowed for entertainment. Public baths, plumbing, and sanitation allowed for a relatively clean environment. But the conquered societies, including Judea, paid dearly for these and other Roman benefits.
Roman Empire, 9AD. Source
Quirinius was the governor of Syria, a region to which, for taxation and administrative purposes, Judea was added. Samaria and Idumea was also under Quirinius' control. Caesar Augustus began a course of census takings at 14-year intervals, for the purposes listed above. These censuses occurred throughout the height of the Roman Empire, until at least around 250 AD. This is why Luke records it as "the first census." (Luke 2:1).
Jews hated the census. It reminded them of their subjugation. They considered it hateful and pagan. They resented the intrusion of it in their lives. Its existence was to force them to pay a denarius in taxes. This equates very roughly to a day's pay at that time. The coins with which they were to pay this tax (coinage was a new-ish invention adapted from the Greeks) with the Emperor's face on it were loathsome to them.
As a matter of fact, when the census was announced, it sparked a huge rebellion. Judas of Galilee rose up, as Acts 5:37 mentions. Barnes' Notes quotes Josephus the historian on this score:
"Yet Judas, taking with him Saddouk, a Pharisee, became zealous to draw them to a revolt, who both said that this taxation was no better than an introduction to slavery, and exhorted the nation to assert their liberty, etc." "This" revolt, he says, was the commencement of the series of revolts and calamities that terminated in the destruction of the city, temple, and nation.The taxes and its census sparked the Judas/Saddouk rebellion and a continual series of uprisings and unrest that led to the ultimate destruction of Temple and the nation in 70AD. So the "first census" introduced in Luke had immediate meaning that Luke's readers would have understood, both historically and emotionally. The census was a big deal.
Fun fact: the denarius was introduced in about 211 BC and was roughly worth 10 donkeys, hence the root part of the word deni meaning "ten each".
Mary and Joseph were obedient, and off they went the 80 or 90 miles upward in the ascent from Nazareth to Bethlehem. Each heavy step for the 9-months' pregnant Mary must have been an ache. Each plodding move must have been a slog, enduring it was for the heavy taxation burdens laid on them, coupled with the onerous burdens of the Pharisaical spiritual encumbrances. Life wasn't easy for the impoverished pair.
Yet as we saw from Mary's Magnificat, her song of praise to the glory of God, that she fully trusted Him. Even though an out-of-wedlock pregnancy was a disaster with potential for stoning or at the least, lifetime of shame and ostracism, she praised God. Even though her pregnancy was a supernatural, implausible event defying comprehension, she praised God.
Joseph, for his part, being a righteous man, (Matthew 1:19) seemed to love Mary, because he resolved to divorce her quietly instead of making her a spectacle as he was within his rights to do.
They determined to fulfill the census requirements, rendering to Caesar what is Caesar's. The two trudged slowly toward their town of origin, not knowing what was ahead for them, but knowing that God did. That was all they needed.
And while they were there, the time came for her to give birth. And she gave birth to her firstborn son and wrapped him in swaddling cloths and laid him in a manger, because there was no place for them in the inn. (Luke 2:6-7)
But the angel said to them, "Do not be afraid; for behold, I bring you good news of great joy which will be for all the people; for today in the city of David there has been born for you a Savior, who is Christ the Lord. "This will be a sign for you: you will find a baby wrapped in cloths and lying in a manger." And suddenly there appeared with the angel a multitude of the heavenly host praising God and saying,
"Glory to God in the highest,
And on earth peace among men with whom He is pleased."
(Luke 2:10-14).