The confusion is easily explained by the fact that thirty-nine saints of this name are mentioned in the Roman Martyrology, eight of whom are commemorated in the one month of January.
[1] Forced by his family to marry, he agreed with his spouse, Basilissa, that they should both preserve their virginity, and further encouraged her to found a convent for women, of which she became the superior, while he himself gathered a large number of monks and undertook their direction.
[2] During the persecution of Diocletian he was arrested, tortured, and put to death at Antioch, in Syria, by the order of the governor, Martian, according to the Latins, at Antinoe, in Egypt, according to the Greeks, which seems more probable.
In the Martyrologium Hieronymianum they are mentioned under 6 January; Usuard, Ado, Notker of St Gall, and others place them under the ninth, and Rabanus Maurus under the thirteenth of the same month, while Vandelbert puts them under 13 February, and the Menology of Canisius under 21 June, the day to which the Greek Menaea assign St. Julian of Caesarea.
[1] Only a fragment of Ælfric's Passion of St. Julian and His Wife Basilissa from his Lives of the Saints has survived, but the traditional legend is there: the two vow not to consummate their marriage on their wedding night, and devote themselves to clænnysse ("chastity").