BIRTHDAY (Dies Natalis). - The Romans commemorated the deceased on the day of their birth; indeed one reads that « Privatae feriae vocantur sacrorum propriorum, velut dies natalis »; thus, the Chronographer (v.) of 354 preserves the natales Caesarum (CIL, I, p. 356). Christians, on the other hand, have always commemorated the day of the earthly death. The date of Dec. 25 is an exception, on which the Church of Rome celebrated the birth of the Redeemer from the first half of the 4th century.
The day of martyrdom is the ἐμέρα γενέθλιος, the true dies natalis of the martyrs (v. MARTIRIO E MARTIRE). St. Peter Chrysologus teaches the faithful that the n. of the saints is not that of their human birth on earth, but from earth into heaven (Sermo 129: PL 52, 555). Therefore in the Hieronymian Martyrology and in the Sacramentaries the anniversary day to be commemorated is called n. In the Acts of Sts. Perpetua and Felicity, the author begins the narrative of the day of their martyrdom with the expression: « inluxit dies victoriae illorum et processerunt de carcere in amphitheatrum quasi in caelum » (P. Franchi de Cavalieri, La Passio SS. Perpetuae et Felicitatis, 5 Supplem. del Röm. Quartalschr. [Rome 1896], p. 138). Also the deacon Pontius, for the day of the martyrdom of the bishop St. Cyprian of Carthage, writes: « illuxit denique dies ille, ille promissus, ille divinus » (CSEL, 3, 3, pp. cvii, 16).
The Calendar of the church of Carthage contains the dies nataliziorum Martyrum (G. B. De Rossi, L. Duchesne, Martyrologium Hieronymianum, in Acta SS. Novembris, II, p. LXX). In a homily on the n. of St. Cyprian, St. Augustine teaches how the Church « natales vocet pretiosas martyrum mortes ». And he adds: « Where can one find today, I do not say in our city, but throughout all Africa and even in the regions overseas, not only a Christian, but also a pagan or Jew or even a heretic who does not say with us the natal day of the martyr Cyprian? And what does this mean, O brethren? We do not know when Cyprian was born, but since on this day he suffered martyrdom, we today celebrate his natal day. We would not, however, celebrate the day of his birth even if we knew it. For on that day he contracted original sin; on this day, instead, he conquered every sin (Sermo 310: PL 38, 1412-13). These concepts were later repeated also in a homily on the natal day of St. Eusebius bishop of Vercelli, once attributed to St. Ambrose (PL 17, 745). On a marble base found in the cemetery of Priscilla was written the date VI idus iulias natale sanctorum martyrum, with the names of the seven martyrs commemorated under the same day in the depositio martyrum (E. Le Blant, D'un nouveau monument relatif aux fils de Ste Felicité, in Mél. d'archéol. et d'hist., 8 [1888], pl. VIII). In St. Paul's, the baker Bitalis was laid to rest on Feb. 11, 401 on the day natale domnes Siteritis (St. Soter: v. E. Diehl, Inscr. latin. christ. veteres, Berlin 1925, no. 2115); at Salona in an epigraph the n. Septimi martyris is indicated for Apr. 18, that is, of the deacon martyr Septimius (id., loc. cit., no. 2116). On a capital of the basilica of Djemila are commemorated for Oct. 1 the natale domni Claudi and on another day the natale domni Pascenti (id., loc. cit., no. 2117). Near Tebessa there is an inscription that indicates for June 11 the natale sancti Varagi or Guaragi and of his companions (id., loc. cit., no. 2118). A. Bosio read in a cemetery of the Via Salaria the epitaph of a Principalis, laid to rest natale s. Susti (St. Sixtus II) that is, on Aug. 6 (id., loc. cit., no. 2121). Of a deceased person buried in the Agro Verano it is said that he died natale sancti Laurenti (id., loc. cit., no. 2122) as is read in the Hieronymian Martyrology for Aug. 10 natale sancti Laurenti. A certain Felicitas was laid to rest on the day natale domnes Theclae (id. loc. cit., no. 2123), a Pascasius died on the day ante natale domni Asteri (id., loc. cit., no. 2124). Tertullian already attests in his time the use of the anniversary of the dead, calling it natalicio: oblationes pro defunctis pro nataliciis annua die facimus (De corona, 3: PL 2, 99); St. Ambrose writes that we Christians forget the day of the birth of the dead, but venerate with solemnity that of their death (De fide resurrectionis, 5: PL 16, 1516). In the inscription of a Claudia Agrippina in the cemetery of Callistus is read cuius dies inluxit, just as in the Passio ss. Perpetuae et Felicitatis and in the life of St. Cyprian (G. B. De Rossi, Paralipomeni del cimitero di Callisto, in Bull. di archeol. crist., 3rd series, 6 [1881], pp. 160-61). F. de Winghe read in St. Mary Major the epitaph of a Lawrence of whom it is said that on the day of death natur est in aeternum (id., Inscr. Chr. Urbis Romae, I, Rome 1861, n. 36).