[6] He was the recipient of letters from Pope Liberius in 353, 354, and 355;[7] and took part in the synod of Milan of 355, where he refused to sign the Arian condemnation of Bishop Athanasius of Alexandria.

In 886, Berengar, Margrave of Friuli, in an act of revenge against Bishop Liutvard, sacked the city of Vercelli, and in particular the episcopal palace and the cathedral.

[10] In September 1050, Pope Leo IX held a synod in Vercelli, directed against simony, against John Scotus' book on the eucharist, and against the heresies of Berengar of Tours.

[13] The seminary of the diocese of Vercelli was established in 1566, by Cardinal Guido Luca Ferrero (1562–1566), after his return from the Council of Trent.

[18] Bishop Giovanni Francesco Bonomigni (1572–1587) was unable to attend the Sixth Provincial Synod of Milan in May 1582, since he was serving as papal nuncio to the Emperor Rudolph in Vienna; he sent his Vicar General, Paulus Granutius, as his procurator.

[19] Bishop Giovanni Stefano Ferrero (1599–1610) was present at the Seventh Provincial Synod of Milan in May 1609 and subscribed the decrees.

Eusebius himself built a church dedicated to S. Theoneste on the site, which was destroyed by the barbarians, and rebuilt by Bishop Albinus in the mid-5th century.

[21] An alternate version, preserved by Benzo of Alba Pompeia,[22] indicates that the church was founded by the Emperor Theodosius the Great (379–395).

[24] The canons of the two institutions fought for hundreds of years over the right to elect a new bishop, precedence, privileges, and income.

[30] The competition and controversy was finally settled on 12 August 1644, when Bishop Giacomo Goria suppressed the Chapter of S. Maria Maggiore and combined all the canons in one body at S. Eusebio.

[42] On 1 June 1772, Pope Clement XIV, at the request of King Charles Emmanuel III of Sardinia, created the new Diocese of Biella, on territories which were removed from the jurisdiction of the bishop of Vercelli.

[45] In a decree issued in Paris on 25 January 1805, Cardinal Giovanni Battista Caprara, the papal legate and archbishop of Milan, carried out a new circumscription of the Cisalpine dioceses.

King Victor Emmanuel I of Sardinia invited Pope Pius VII to restore the good order of the Church in his kingdom, which had been disrupted by the French occupation.

On 17 July 1817, the pope issued the bull "Beati Petri", which began by establishing de novo the ten dioceses which had been suppressed under the French, and delimiting the extent of each in detail,[47] including Vercelli and the restored Biella.

Pope John Paul II made a Papal visit to Vercelli in May 1998, during which he declared the priest Secondo Pollo (d. 1941) to be "Blessed".