Juliani, Basilissae, et socii

Holweck, p. 201: "Since the acts of S. Julian are fictitious, the existence of this martyr [Celsus] must be questioned."; Holweck, p. 570;

Several dates exist for the feast, possibly due to concurrence with Epiphany. It is 6 January in the Martyrologium Hieronymianum, but 9 January in the Roman Martyrology and various other witnesses, 8 January in the Greek Menaea, and 13 January in Hrabanus Maurus (see Léon Cluget, "Julian and Basilissa," Catholic Encylopedia, (1913)).
Alban Butler, in "The lives of the fathers, martyrs, and other principal saints," claims "it was deferred in different churches to the 7, 8, 9, 10, 11, 12, 13, 14, 17, 27, 28, or 29th, of January; 12, 13, 14, 17, 19, 24, or 27th, of February; 20, 21, or 22d of June; or 31st of August."

Spanish manuscripts tend to place Julian and Basilissa on 7 January, while V-CVbav San Pietro B.79 has a commemoration for Julian and Celsus at Vespers on January 12.