The following are excerpts from the Catholic Encyclopedia from the article on "Christmas:"

The word for Christmas in late Old English is Cristes Maesse, the Mass of Christ, first found in 1038, and Cristes-messe, in 1131. In Dutch it is Kerst-misse, in Latin Dies Natalis, whence comes the French Noël .....

EARLY CELEBRATION Christmas was not among the earliest festivals of the Church. Irenaeus and Tertullian omit it from their lists of feasts; Origen, glancing perhaps at the discreditable imperial Natalitia, asserts (in Lev. Hom. viii in Migne, P.G., XII, 495) that in the Scriptures sinners alone, not saints, celebrate their birthday; Arnobius (VII, 32 in P.L., V, 1264) can still ridicule the "birthdays" of the gods.

Alexandria. The first evidence of the feast is from Egypt. About A.D. 200, Clement of Alexandria (Strom., I, xxi in P.G., VIII, 888) says that certain Egyptian theologians "over curiously" assign, not the year alone, but the day of Christ's birth, placing it on 25 Pachon (20 May) in the twenty-eighth year of Augustus. [Ideler (Chron., II, 397, n.) thought they did this believing that the ninth month, in which Christ was born, was the ninth of their own calendar.] Others reached the date of 24 or 25 Pharmuthi (19 or 20 April). With Clement's evidence may be mentioned the "De paschæ computus", written in 243 and falsely ascribed to Cyprian (P.L., IV, 963 sqq.), which places Christ's birth on 28 March, because on that day the material sun was created. But Lupi has shown (Zaccaria, Dissertazioni ecc. del p. A.M. Lupi, Faenza, 1785, p. 219) that there is no month in the year to which respectable authorities have not assigned Christ's birth. Clement, however, also tells us that the Basilidians celebrated the Epiphany, and with it, probably, the Nativity, on 15 or 11 Tybi (10 or 6 January). At any rate this double commemoration became popular, partly because the apparition to the shepherds was considered as one manifestation of Christ's glory, and was added to the greater manifestations celebrated on 6 January; partly because at the baptism-manifestation many codices (e.g. Codex Bezæ) . . . . . .

Abraham Ecchelensis (Labbe, II, 402) quotes the Constitutions of the Alexandrian Church for a dies Nativitatis et Epiphaniæ in Nicæan times; Epiphanius (Hær., li, ed. Dindorf, 1860, II, 483) quotes an extraordinary semi-Gnostic ceremony at Alexandria in which, on the night of 5-6 January, a cross-stamped Korê was carried in procession round a crypt, to the chant, "Today at this hour Korê gave birth to the Eternal"; John Cassian records in his "Collations" (X, 2 in P.L., XLIX, 820), written 418-427, that the Egyptian monasteries still observe the "ancient custom"; but on 29 Choiak (25 December) and 1 January, 433, Paul of Emesa preached before Cyril of Alexandria, and his sermons (see Mansi, IV, 293; appendix to Act. Conc. Eph.) show that the December celebration was then firmly established there, and calendars prove its permanence. The December feast therefore reached Egypt between 427 and 433.

Cyprus, Mesopotamia, Armenia, Asia Minor. In Cyprus, at the end of the fourth century, Epiphanius asserts against the Alogi (Hær., li, 16, 24 in P. G., XLI, 919, 931) that Christ was born on 6 January and baptized on 8 November. Ephraem Syrus (whose hymns belong to Epiphany, not to Christmas) proves that Mesopotamia still put the birth feast thirteen days after the winter solstice; i.e. 6 January; Armenia likewise ignored, and still ignores, the December festival. . . . . .

Jerusalem. . . . . . In 385, therefore, 25 December was not observed at Jerusalem. This checks the so-called correspondence between Cyril of Jerusalem (348-386) and Pope Julius I (337-352), quoted by John of Nikiu (c. 900) to convert Armenia to 25 December (see P.L., VIII, 964 sqq.). Cyril . . . . . . asks Julius to assign the true date of the nativity "from census documents brought by Titus to Rome"; Julius assigns 25 December. . . . . . .

Rome. . . . . . . In the civil calendar 25 December is marked "Natalis Invicti". In the "Depositio Martyrum" a list of Roman or early and universally venerated martyrs, under 25 December is found "VIII kal. ian. natus Christus in Betleem Iudeæ". . . . . . . In the list of consuls are four anomalous ecclesiastical entries: the birth and death days of Christ, the entry into Rome, and martyrdom of Saints Peter and Paul. The significant entry is "Chr. Cæsare et Paulo sat. XIII. hoc. cons. Dns. ihs. XPC natus est VIII Kal. ian. d. ven. luna XV," i.e. during the consulship of (Augustus) Cæsar and Paulus Our Lord Jesus Christ was born on the eighth before the calends of January (25 December), a Friday, the fourteenth day of the moon. The details clash with tradition and possibility. The epact, here XIII, is normally XI; the year is A.U.C. 754, a date first suggested two centuries later; in no year between 751 and 754 could 25 December fall on a Friday; . . . . . .

The Gospels. Concerning the date of Christ's birth the Gospels give no help; upon their data contradictory arguments are based. The census would have been impossible in winter: a whole population could not then be put in motion. . . . . .

Editorial Note: We would like to encourage the reader to read this entire article from the web page listed above.

The conclusion is that NO ONE knows the exact date when Jesus was born. The Bible does give us the general time period of when Jesus was born and it was NOT on December 25th.