Luke also in the opening description puts his narrative onto a historical foundation by citing a census during the period:
In those days a decree went out from Caesar Augustus that all the world should be enrolled. 2 This was the first enrollment, when Quirinius was governor of Syria. 3 And all went to be enrolled, each to his own city. 4 ¶ And Joseph also went up from Galilee, from the city of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David,
The census serves many roles in Luke’s narrative;: Dr. Sri explains that “being forced to submit to a Roman enrollment to pay the required taxes would been a difficult reminder for the Jews of their oppressed conditions…on one level, the story of Mary and Joseph’s traveling to Bethlehem highlights Caesar’s worldwide dominance…Caesar’s powerful decree ironically serves God’s larger plan for the Messiah-King to be born in his proper city, Bethlehem”
The typology of this particular passage to the old testament brings us to a prophecy of Micah:
But you, O Bethlehem Ephrathah,
who are little to be among the clans of Judah,
from you shall come forth for me
one who is to be ruler in Israel,
whose origin is from of old,
from ancient days. 
So, naturally, in our skeptical age, it begs the question, what is the historical evidence for such a census? Professor of Ancient History at Western Michigan University, Paul L. Maier writes in his work In The Fullness of Time: A Historian Looks at Christmas, Easter, and the Early Church, “That Mary ever had to endure the rigors of this eighty-mile journey on the back of a jogging donkey while in a state of very advanced pregnancy has been doubted by some scholars. Rome never required her subjects to return to their original homes for such enrollments, they claim, and Luke must have garbled the facts. But this view has been disproved by the discovery of a Roman census edict from 104 A.D. in neighboring Egypt, in which taxpayers who were living elsewhere were ordered to return to their original homes for registration.”
Fr. Raymond E. Brown writes on the topic in his work Birth of the Messiah:
“Would a Roman census have sent people back to their tribal or ancestral homes to be enrolled, as Luke describes in the case of Joseph? We have no clear parallel for such a practice. Since enrollment was primarily for taxation purposes, the general Roman pattern was to register people where they lived or in the nearby principal city of a district (the city from which the tax would be collected). A papyrus (Lond. 904, 20f.) describes a census in Egypt in a.d. 104 wherein a temporary dweller, in order to be enrolled, had to go back to the area of his regular domicile where he had a house. (Sometimes this is referred to as a kata oikian census.) Obviously this ruling was motivated by tax considerations about property and agriculture; and it offers little support for sending Joseph from Nazareth where he permanently resided”
Fr. Brown indicates that the Egyptian document presented by Maier, in fact, does not prove the necessity for Joseph going to Bethlehem because the Gospel of Luke indicates itself that Joseph had no property in the region which is the qualified indicator in the Egyptian document for travel, “7 And she gave birth to her first-born* son and wrapped him in swaddling cloths, and laid him in a manger, because there was no place for them in the inn.  Fr. Brown ultimately comes to the conclusion that due to the inconsistencies of where the Holy Family is staying prior to and after the birth of Christ that scholars and theologians have to look at the theological implications of the author’s written work, “Now biblical scholarship seems to be moving into a more fruitful stage of research as it seeks to recover the value of the infancy stories as theology. In the last twenty years in general Gospel research, attention has shifted away from the pre-Gospel history of narratives and sayings about Jesus to the role of those narratives and sayings in the finished Gospels. What message is the evangelist trying to convey to the Church through them?”
However, Pope Benedict XVI in his work on the Infancy Narrative gives a long rebuttal on the skeptical approach of Fr. Brown and other scholars. Fr. Brown stresses in his work the error in the dating due to Herod the Great dying 4 B.C., Pope Benedict XVI writing a decade later gives further support to Maier’s argument by recent scholarship point to an error in our dating calendar by Dionysius, as well as indicating that although Quirinius was not the governor during the period, records indicate that he could have been in the region during the birth of Christ around 4 B.C.:
One initial problem can be solved quite easily: the census took place at the time of King Herod the Great, who actually died in the year 4 B.C. The starting-point for our reckoning of time—the calculation of Jesus’ date of birth—goes back to the monk Dionysius Exiguus († c. 550), who evidently miscalculated by a few years. The historical date of the birth of Jesus is therefore to be placed a few years earlier. There is much debate regarding the date of the census. According to Flavius Josephus, to whom we owe most of our knowledge of Jewish history around the time of Jesus, it took place in the year 6 A.D. under the governor Quirinius, and as it was ultimately a question of money, it led to the uprising of Judas the Galilean (cf. Acts 5:37). According to Josephus it was only then, and not before, that Quirinius was active in the region of Syria and Judea. Yet these claims in their turn are uncertain. At any rate, there are indications that Quirinius was already in the Emperor’s service in Syria around 9 B.C. So it is most illuminating when such scholars as Alois Stöger suggest that the “population census” was a slow process in the conditions of the time, dragging on over several years. Moreover, it was implemented in two stages: firstly, registration of all land and property ownership, and then—in the second phase—determination of the payments that were due. The first stage would have taken place at the time of Jesus’ birth; the second, much more injurious for the people, was what provoked the uprising (cf. Stöger, Lukasevangelium, pp. 372f.). Some have raised the further objection that there was no need, in a census of this kind, for each person to travel to his hometown (cf. Lk 2:3). But we also know from various sources that those affected had to present themselves where they owned property. Accordingly, we may assume that Joseph, of the house of David, had property in Bethlehem, so that he had to go there for tax registration.”
 RSV Lk 2:1–4.
 Sri, 71.
 RSV Mic 5:2.
 Paul L Maier, In The Fullness of Time: A Historian Looks at Christmas, Easter, and the Early Church ( Grand Rapids: Kregel Publications, 1991), 4.
 Raymond E. Brown, The Birth of the Messiah: A Commentary on the Infancy Narratives in the Gospels of Matthew and Luke, New Updated Edition. (New York; London: Yale University Press, 1993), 549.
 RSV Lk 2:7.
 Brown, 37–38.
 Pope Benedict XVI, The Infancy Narrative, 62-63