AOSTA, DIOCESE OF. - It comprises the entire territory of the Aosta Valley (Piedmont) and has 90,000 inhabitants, 88 parishes, 140 secular priests, 5 male religious orders and congregations, and 7 female ones, as well as major and minor seminaries. Patron: St. Gratus, bishop, whose feast is celebrated on September 7.
History. - Aosta, the ancient Augusta Praetoria, was founded in 25 BC at the convergence of the two roads leading to the Graian Alps (Little St. Bernard) and the Pennine Alps (Great St. Bernard); the colony of Augusta Praetoria, composed of praetorians and the ancient inhabitants of the valley, the Salassi, was included in the 11th region of Italy under Augustus. With the fall of the empire, the Aosta Valley belonged to the Ostrogoths, the Byzantines, the Lombards, and from 575 until the advent of the Carolingians, to the Merovingian kingdom of Burgundy; after the fall of the Carolingians, it followed the fortunes of the kingdom of Italy and by the mid-10th century was again included within the territory of the kingdom of Burgundy. At the beginning of the 11th century, the Aosta Valley begins to appear in the Alpine Burgundian group of domains of Humbert I of Savoy, and although it belonged to the empire, in practice it knew no other lords besides the House of Savoy, to whom it remained most faithful until its annexation to Italy. Aosta, elevated to a duchy in 1238, governed itself with great liberties through the Assembly of the Three Estates—clergy, nobility, and people—the Council of Commissioners, established in 1535–36, and its own laws, codified in 1586 (*Costumes générales du Duché d'Aoust*, Chamberlain 1588); however, Charles Emmanuel III abolished all of these between 1760 and 1770. The official language of the duchy was French. Aosta so successfully defended the integrity of its territory that it earned the title *Aoste la Pucelle* ("Aosta the Maiden").
As throughout Upper Italy, Christianity spread slowly in the Aosta Valley; its systematic evangelization occurred during the 4th century, probably through the efforts of St. Eusebius of Vercelli, whose diocese extended as far as the Graian and Pennine Alps. The erection of the diocese dates to the beginning of the 5th century, and its first bishop was Eustasius, who, certainly due to his advanced age, was represented by the priest Gratus at the Council of Milan in 451. Indeed, the small cemetery basilica, recently discovered in a cemetery area near the Porta Decumana on the road leading to the Little St. Bernard, may date to the late 4th century (cf. C. Carducci, in *Bollettino del Centro di Studi Archeologici ed Artistici del Piemonte*, I [1941], p. 5).
The catalog of bishops of Aosta is fragmentary until nearly the end of the 11th century. Among them deserve particular mention: St. Gratus (q.v.); St. Jocundus, under whose episcopate St. Orso (q.v.) lived in Aosta; Anselm I (early 10th century), who rebuilt the collegiate church of SS. Peter and Orso, of which traces of decoration still remain under the roof of the present church; Gualbert (d. 1212), who obtained from Count Thomas I of Savoy in 1191 the first charter of privileges for Aosta; the Blessed Boniface of Valperga (1220–1243), whose cult was confirmed in 1800; the Blessed Emeric of Quart (1301–1313), whose cult was confirmed in 1881; Peter Hyacinth (1588–1597), who, together with the Three Estates, stifled Protestant propaganda in the Valley; Marc’Antonio Bobba (1557–1568), a jurist who took part in the Council of Trent and became a cardinal (d. 1575); Peter Francis of Sales (1741–1783), who in 1780 gave the major seminary its present seat; and August Joseph Duc (q.v.; 1872–1907), a noted historian of the diocese to whom the present minor seminary is due.
The diocese of Aosta was a suffragan of Milan until Charlemagne incorporated it into the ecclesiastical province of Tarentaise, which he created at the end of the 8th century; however, by the mid-9th century, Aosta returned to Milan for a century, then reverted to the Tarentaise province and remained there until 1802. The diocese was then suppressed and united with Ivrea; upon its restoration (1817), it was attached to the new ecclesiastical province of Chambéry and remained there until 1864, after which it passed to that of Turin. The diocese of Aosta, like many others, had a particular rite, which was suppressed on February 4, 1829, by Leo XII with the bull *In Pedemontii Ecclesias*.
Among the illustrious ecclesiastical figures worthy of mention are: St. Bernard (q.v.), restorer of the hospices of the Great and Little St. Bernard; St. Anselm (q.v.); Cardinal Antonio of Challant (q.v.); Prior Giorgio of Challant (d. 1509), a patron of the arts; Fr. Antonio Savio (*a sapientibus*), general of the Conventuals, who took part in the Council of Trent (d. 1566); Canon Antonio Gal, father of Aosta Valley history; and Fr. Lorenzo, a learned and zealous Capuchin (d. 1880).
There were no monasteries or abbeys in the diocese, but there were several Benedictine priories from the 11th century onward, as well as various houses of canons regular, including the present-day residence of the Canons Regular of the Great St. Bernard and the provostship of Verrès, which dates to the late 10th century and passed to the Canons Regular of the Lateran in 1911. The principal institute of ecclesiastical culture is the Religious and Scientific Academy of St. Anselm, founded in 1855 by Canon A. Gal, which has given a strong impetus to local historical studies, has published its own bulletin since its inception, and possesses a fine library and a small museum. The main library of the diocese is that of the seminary, not yet cataloged. The archives of the bishop, the cathedral, the collegiate church of St. Orso (arranged chronologically), and the municipality are rich in codices (from the 9th century onward) and documents (parchments from the 11th century onward).
Monuments. - The city has many Roman monuments: the Arch of Augustus, the Porta Pretoria, the theater (now excavated), the amphitheater, the cryptoportico, etc.; the cathedral and the collegiate church of St. Orso, reduced to their present state in the 15th century, are not notable from an architectural standpoint, except for their two ancient crypts. However, they contain numerous and very precious works of art: the cathedral preserves the well-known ivory diptych of Honorius from 406, a fibula with a large cameo of Roman art set in 13th-century gold filigree, the artistic reliquary chests of St. Gratus (1458) and St. Jocundus (1615), and ornate vestments from the 15th century onward, illuminated missals and choir books, the carved wooden stalls in the choir from 1477, etc.; the collegiate church, in addition to the 10th-century paintings already noted, has 15th-century vault paintings and 15th-century carved wooden stalls in the choir, as well as precious illuminated missals from the 15th century, reliquaries, chalices, etc. Adjacent to the church is the majestic bell tower from the 12th–13th centuries; the Romanesque cloister from 1133; the priory, decorated externally with terracottas from the late 15th century; and the Roman museum. Several extra-urban parishes also possess notable monuments and artworks, which were displayed in the first Sacred Art Exhibition held in Aosta in 1936.