Saint Nicomedes was a Martyr of unknown era, whose feast is observed 15 September. The Roman Martyrologium and the historical Martyrologies of Bede and his imitators place the feast on this date. The Gregorian Sacramentary contains under the same date the orations for his Mass. The name does not appear in the three oldest and most important Manuscripts of the Martyrologium Hieronymianum, but was inserted in later recensions ("Martyrol. Hieronymianum", ed. G. B. de Rossi-L. Duchesne, in Acta SS., November II, 121). The saint is without doubt a martyr of the Roman Church.