And it came to pass in those days, there went out a decree from Caesar Augustus, hat all the world should be taxed . . . And all went to be taxed, everyone into his own city. (Luke 2:1, 3)
When discussing the historicity of the census in Luke 2, F.F. Bruce offered the following piece of evidence:
There is explicit evidence that the practice of requiring each householder to return to his original home for census purposes was enforced in Egypt. A papyrus document of A.D. 104 has preserved a decree of the prefect of Egypt embodying just such a direction for householders in his province. Once again, the evidence comes from Egypt because such evidence is most easily preserved in Egypt, but the practice need not have been confined to Egypt. (F.F. Bruce, Jesus and Christian Origins Outside the New Testament [London: Hodder and Stoughton, 1984], 194)
The papyrus Bruce references in a footnote is that of Papyrus London 904. The following is an image of the text:
One online source summarises the document thusly:
Papyrus Census Order
From Egypt, 104 CE, Ht. 22.2 cm. BL Papyrus 904.
A papyrus document containing a command in Greek from the Prefect Gaius Vibius Maximus for all those in his area of authority to return to their own homes for the purposes of a census (apogaphēs). This illustrates a situation in the time of Trajan analogous to that described by Luke at the time of the birth of Christ (Luke 2-1-4), when Augustus decreed that a census should be taken of the Roman world.
At least one criticism levelled against the historicity of Luke's account, the purported claim that a census requiring people to go back home to their original house is nonsense is soundly refuted by the evidence.