SAINT ORSO. - In the Roman Martyrology three saints of this name are commemorated: 1) St. U., companion of St. Victor, martyrs of Solothurn (Switzerland), counted among the martyrs of the so-called Theban Legion. Feast on 30 October (BHL, 8584-85; H. Quentin, Les martyrologes historiques du moyen âge, Paris 1908, pp. 280-82; Martyr. Romanum, p. 426). 2) St. U., bishop of Ravenna (d. between 424 and 429), builder and consecrator of the Cathedral, the Anastasis, later called the Basilica Ursiana. Feast on 13 April (BHL, 8455; Lanzoni, p. 749; C. Ricci, Guida di Ravenna, Bologna [1923], pp. 37-45; Martyr. Romanum, p. 137); 3) St. U., bishop of Auxerre between the end of the 5th century and the beginning of the 6th. Feast on 30 July (L. Duchesne, Fastes épiscopaux de l'ancienne Gaule, II, Paris 1910, p. 445; Martyr. Romanum, p. 314).
Among the other saints of this name, worthy of remembrance is St. U. of Aosta, much venerated in the regions of the western Alps as a protector of the countryside: he is invoked in the dangers of floods; to obtain rain, against fever and diseases of livestock, etc. Little is known of his life, except for certain edifying episodes that form the plot of the brief Vita s. Ursi, preserved in two almost identical redactions: the first, in codices of the 9th-10th century and later, unpublished (BHL, Suppl. p. 301; M. Coens, in Anal. Bolland., 52 [1934], p. 259; the present writer has its edition ready); the second, in codices of the 11th century and later, published (BHL, 8453, interpolated; anonymous, L'Insigne Collégiale d'Aoste, Ivrea 1929, pp. 9-23, non-interpolated). St. U. appears there as the priest in charge of the church of St. Peter extra moenia (a cemetery church, which later became the collegiate church of Sts. Peter and U.) at the time of the unworthy bishop of Aosta Plocanus, not known from other sources, who would have lived in the 6th century. The Irish origin of St. U. of Aosta does not seem earlier than the Liber anniversariorum... (1554) of the Chapter of the cathedral of Aosta (ed. A. Gal, in Mon. Historiae Patriae. Scriptores, III, Turin 1848, p. 618); in fact the manuscript liturgical books of the Aosta Valley and the same Breviarium ad Alme Augusten.

Ecclesie ritum..., Turin 1532, fols. CCXIV-XV, make no mention of it. St. U. has also been erroneously made bishop of Aosta and martyr, confusing him with the martyr U. who appears in the legendary Passio Theonesti of Altino (cf. BHL, 8110-14; Lanzoni, pp. 907-909, 1052-53, 1056). Feast on 1 February.
Bibliography4 works
A. Pietro Frutaz