Saint Eusebius of Vercelli has multiple feast days. The traditional feast, today, is not the day of his death, which was August 1st, and his modern feast day is August 2nd. December 16th is the approximate date of his elevation as bishop.
Lives of the Saints by Alban Butler.
Lives of the Saints by Sabine Baring-Gould.
The Liturgical Year by Dom Guéranger.
The lives of saints, with other feasts of the year, according to the Roman calendar by Peter Ribadeneira.
Pope Benedict XVI on Eusebius of Vercelli.
Writing of Saint Eusebius
A brief letter written by Saint Eusebius of Vercelli to the Emperor Constantine.
Art & Architecture
The Cathedral of Vercelli is dedicated to Saint Eusebius, and it has an ambo sculpted by Benedetto Antelami, a Romanesque sculptor whose work I love, but I have not yet found a photograph of it.
The Saints in Art by Joseph Maria von Radowitz.
Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.