SION (SITTEN), DIOCESI di. — City and diocese, capital of the canton of Valais in Switzerland. Its area is 5235 sq. km, with a population of 150,000 inhabitants, of whom 145,000 are Catholics; it has 145 parishes served by 251 diocesan priests and 148 religious priests; it has 18 male and 33 female religious communities (Ann. Pont. 1953, p. 402).
Its origins date from the first centuries A.D., and it was called “Sedunum.” Valais was conquered by Augustus around 8 B.C. In 377 it was certainly already Christian, since an ancient inscription bearing the monogram of Christ dates from that period. The present diocese extends over the entire territory of the Canton, except for five municipalities, and its boundaries have changed little over the centuries.
The first known bishop is Theodore, “episcopus Octodurensis,” as he subscribed himself at the Councils of Aquileia (381) and Milan (390); he established his see at Octodurum (Martigny); he founded the church of S. Maurizio in honor of the martyrs of the Theban Legion at Agaunum (v.); he was followed by the bishops Salvius and Protasius; Constantius attended the Council of Epaona (517), and Rufus those of Orléans (541 and 549); Heliodorus probably transferred the see to S. around 585; it is certain, however, that Leudomond established it there definitively in 613. Protasius attended the Council of Chalon-sur-Saône (650); Vulcherius, formerly metropolitan of Vienne, was at once bishop of S. and abbot of S. Maurizio: in 771 he paid homage to Charlemagne; his funerary inscription is preserved (P. Bourban, L'archevêque et Vultchaire et son inscription funéraire, in Comptes rendus du IV Congrès scientifique international des catholiques, Friburgo 1898, 10e sez., pp. 19-35).
In the fourth century S. depended on the metropolitan see of Milan; it then passed, around the middle of the fifth century, under that of Vienne and, toward the end of the eighth century, under that of Tarentaise. The oldest lists of the bishops of S. date from the sixteenth century. The first seven resided at Octodurum, from Theodore I (380–91) to Agricola (565); the other 76 at S., from Heliodorus (585) to the last, Monsignor Bieler (1919–52). The apex of episcopal power in S. extended from 999 to 1032, when the bishop was count and representative of the Emperor, minister of justice of the army, and secular prince: the last bishop to bear this title was Monsignor P. J. de Proux (1843–75): Sacri Romani Imperii princeps. The most imposing figure in the history of the
diocese of S. is Cardinal Matteo Schiner (born at Mühlebach, died in Rome in 1522 and buried in the church of the Anima). Cardinal Schiner truly dominated his age, including from the international point of view. He brought Valais into the Swiss Confederation and had the merit of making his see independent; he had ascended it in 1499, and Julius II immediately declared it directly subject to the Holy See between 1510 and 1513.
Since 1919, the bishop of S. has been elected directly by the Holy See; the choice is made from among the diocesan clergy, as for all the Swiss dioceses, by virtue of particular concordats. Valais is bilingual; consequently, French is spoken in the lower regions and German in the upper regions: the newly elected bishop is chosen alternately from one region and the other.
Until the eighteenth century, the diocese had no institutions for the formation of the clergy. From the thirteenth century onward, the people of Valais studied at the Sorbonne in Paris, at Friburgo in Br., Bologna, Rome, Vienna, and Milan. In 1585, 1607, and 1624, petitions were sent to the Holy See requesting places for theology students in Rome. Urban VIII established two scholarships in Vienna in 1627. S. Carlo Borromeo founded two places in Milan for students from Valais; other foundations were established subsequently. From 1858 the students left Vienna for Innsbruck. Today theology students attend Friburgo and Rome. The first episcopal seminary was founded in 1748. The school of theology was opened in 1874 near the Cathedral. In 1927 a minor seminary with a gymnasium was established. In the municipality of S. an inscription dated to the year 377 is preserved; it constitutes the oldest example of an epigraph intended for a public monument bearing the monogram of Christ (E. Le Blant, Inscriptions chrétiennes de la Gaule, I, Parigi 1856, n. 369, pp. 496–97, tav. 231; CIL, XII, 138). — Vedi tav. XLIII.