When Was Jesus Born
The first evidence of the Christmas feast is from Egypt. 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.
In Cappadocia, Gregory of Nyssa's sermons on St. Basil (who died before 1 January, 379) and the two following, preached on St. Stephen's feast (P.G., XLVI, 788; cf, 701, 721), prove that in 380 the 25th December was already celebrated there, unless, following Usener's too ingenious arguments (Religionsgeschichtliche Untersuchungen, Bonn, 1889, 247-250), one were to place those sermons in 383.
In Antioch, on the feast of St. Philogonius, Chrysostom preached an important sermon. The year was almost certainly 386, though Clinton gives 387, and Usener, by a long rearrangement of the saint's sermons, 388 (Religionsgeschichtl. Untersuch., pp. 227-240). But between February, 386, when Flavian ordained Chrysostom priest, and December is ample time for the preaching of all the sermons under discussion. (See Kellner, Heortologie, Freiburg, 1906, p. 97, n. 3). In view of a reaction to certain Jewish rites and feasts, Chrysostom tries to unite Antioch in celebrating Christ's birth on 25 December, part of the community having already kept it on that day for at least ten years. In the West, he says, the feast was thus kept, anothen; its introduction into Antioch he had always sought, conservatives always resisted. This time he was successful; in a crowded church he defended the new custom. It was no novelty; from Thrace to Cadiz this feast was observed — rightly, since its miraculously rapid diffusion proved its genuineness. Besides, Zachary, who, as high-priest, entered the Temple on the Day of Atonement, received therefore announcement of John's conception in September; six months later Christ was conceived, i.e. in March, and born accordingly in December. Finally, though never at Rome, on authority he knows that the census papers of the Holy Family are still there. [This appeal to Roman archives is as old as Justin Martyr (First Apology 34-35) and Tertullian (Adv. Marc., IV, 7, 19). Julius, in the Cyriline forgeries, is said to have calculated the date from Josephus, on the same unwarranted assumptions about Zachary as did Chrysostom.] Rome, therefore, has observed 25 December long enough to allow of Chrysostom speaking at least in 388 as above (P.G., XLVIII, 752, XLIX, 351).
In 379 or 380 Gregory Nazianzen made himself exarchos of the new feast, i.e. its initiator, in Constantinople, where, since the death of Valens, orthodoxy was reviving. His three Homilies (see Hom. xxxviii in P.G., XXXVI) were preached on successive days (Usener, op. cit., p. 253) in the private chapel called Anastasia. On his exile in 381, the feast disappeared. According, however, to John of Nikiû, Honorius, when he was present on a visit, arranged with Arcadius for the observation of the feast on the Roman date. Kellner puts this visit in 395; Baumstark (Oriens Chr., 1902, 441-446), between 398 and 402. The latter relies on a letter of Jacob of Edessa quoted by George of Beeltân, asserting that Christmas was brought to Constantinople by Arcadius and Chrysostom from Italy, where, "according to the histories", it had been kept from Apostolic times. Chrysostom's episcopate lasted from 398 to 402; the feast would therefore have been introduced between these dates by Chrysostom bishop, as at Antioch by Chrysostom priest.
At Rome the earliest evidence is in the Philocalian Calendar (P.L., XIII, 675; it can be seen as a whole in J. Strzygowski, Kalenderbilder des Chron. von Jahre 354, Berlin, 1888), compiled in 354, which contains three important entries. 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". On "VIII kal. mart." (22 February) is also mentioned St. Peter's Chair. 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; tradition is constant in placing Christ's birth on Wednesday. Moreover the date given for Christ's death (duobus Geminis coss., i.e. A.D. 29) leaves Him only twenty eight, and one-quarter years of life. Apart from this, these entries in a consul list are manifest interpolations. But are not the two entries in the "Depositio Martyrum" also such? Were the day of Christ's birth in the flesh alone there found, it might stand as heading the year of martyrs' spiritual natales; but 22 February is there wholly out of place. Here, as in the consular fasti, popular feasts were later inserted for convenience' sake. The civil calendar alone was not added to, as it was useless after the abandonment of pagan festivals. So, even if the "Depositio Martyrum" dates, as is probable, from 336, it is not clear that the calendar contains evidence earlier than Philocalus himself, i.e. 354, unless indeed pre-existing popular celebration must be assumed to render possible this official recognition. Were the Chalki manuscript of Hippolytus genuine, evidence for the December feast would exist as early as c. 205. The relevant passage [which exists in the Chigi manuscript Without the bracketed words and is always so quoted before George Syncellus (c. 1000)] runs:
He gar prote parousia tou kyriou hemon he ensarkos [en he gegennetai] en Bethleem, egeneto [pro okto kalandon ianouarion hemera tetradi] Basileuontos Augoustou [tessarakoston kai deuteron etos, apo de Adam] pentakischiliosto kai pentakosiosto etei epathen de triakosto trito [pro okto kalandon aprilion, hemera paraskeun, oktokaidekato etei Tiberiou Kaisaros, hypateuontos Hrouphou kai Hroubellionos. — (Comm. In Dan., iv, 23; Brotke; 19)
"For the first coming of Our Lord in the flesh [in which He has been begotten], in Bethlehem, took place [25 December, the fourth day] in the reign of Augustus [the forty-second year, and] in the year 5500 [from Adam]. And He suffered in His thirty-third year [25 March, the parasceve, in the eighteenth year of Tiberius Cæsar, during the consulate of Rufus and Rubellio]."
Interpolation is certain, and admitted by Funk, Bonwetsch, etc. The names of the consuls [which should be Fufius and Rubellius] are wrong; Christ lives thirty-three years; in the genuine Hippolytus, thirty-one; minute data are irrelevant in this discussion with Severian millenniarists; it is incredible that Hippolytus should have known these details when his contemporaries (Clement, Tertullian, etc.) are, when dealing with the matter, ignorant or silent; or should, having published them, have remained unquoted (Kellner, op. cit., p. 104, has an excursus on this passage.)
By the time of Jerome and Augustine, the December feast is established, though the latter (Epp., II, liv, 12, in P.L., XXXIII, 200) omits it from a list of first-class festivals. From the fourth century every Western calendar assigns it to 25 December. At Rome, then, the Nativity was celebrated on 25 December before 354; in the East, at Constantinople, not before 379, unless with Erbes, and against Gregory, we recognize it there in 330. Hence, almost universally has it been concluded that the new date reached the East from Rome by way of the Bosphorus during the great anti-Arian revival, and by means of the orthodox champions. De Santi (L'Orig. delle Fest. Nat., in Civiltæ Cattolica, 1907), following Erbes, argues that Rome took over the Eastern Epiphany, now with a definite Nativity colouring, and, with as increasing number of Eastern Churches, placed it on 25 December; later, both East and West divided their feast, leaving Ephiphany on 6 January, and Nativity on 25 December, respectively, and placing Christmas on 25 December and Epiphany on 6 January.
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. Again, in winter it must have been; then only field labour was suspended. But Rome was not thus considerate. Authorities moreover differ as to whether shepherds could or would keep flocks exposed during the nights of the rainy season.
The earliest rapprochement of the births of Christ and the sun is in Cyprian, "De pasch. Comp.", xix, "O quam præclare providentia ut illo die quo natus est Sol . . . nasceretur Christus." — "O, how wonderfully acted Providence that on that day on which that Sun was born . . . Christ should be born." In the fourth century, Chrysostom, "del Solst. Et Æquin." (II, p. 118, ed. 1588), says: "Sed et dominus noster nascitur mense decembris . . . VIII Kal. Ian. . . . Sed et Invicti Natalem appelant. Quis utique tam invictus nisi dominus noster? . . . Vel quod dicant Solis esse natalem, ipse est Sol iustitiæ." — "But Our Lord, too, is born in the month of December . . . the eight before the calends of January [25 December] . . ., But they call it the 'Birthday of the Unconquered'. Who indeed is so unconquered as Our Lord . . .? Or, if they say that it is the birthday of the Sun, He is the Sun of Justice." Already Tertullian (Apol., 16; cf. Ad. Nat., I, 13; Orig. c. Cels., VIII, 67, etc) had to assert that Sol was not the Christians' God; Augustine (Tract xxxiv, in Joan. In P.L., XXXV, 1652) denounces the heretical identification of Christ with Sol. Pope Leo I (Serm. xxxvii in nat. dom., VII, 4; xxii, II, 6 in P.L., LIV, 218 and 198) bitterly reproves solar survivals — Christians, on the very doorstep of the Apostles' basilica, turn to adore the rising sun. Sun-worship has bequeathed features to modern popular worship in Armenia, where Christians had once temporarily and externally conformed to the cult of the material sun (Cumont, op. cit., p. 356). But even should a deliberate and legitimate "baptism" of a pagan feast be seen here no more than the transference of the date need be supposed. The "mountain-birth" of Mithra and Christ's in the "grotto" have nothing in common: Mithra's adoring shepherds (Cumont, op. cit., I, ii, 4, p. 304 sqq.) are rather borrowed from Christian sources than vice versa.
Other theories of pagan origin
The origin of Christmas should not be sought in the Saturnalia (1-23 December) nor even in the midnight birth at Eleusis (see J.E. Harrison, Prolegom., p. 549) with its probable connection through Phrygia with the Naasene heretics, or even with the Alexandrian ceremony quoted above; nor yet in rites analogous to the midwinter cult at Delphi of the cradled Dionysus, with his revocation from the sea to a new birth (Harrison, op. cit., 402 sqq.).