Allerheiligenlitanei
Immediately after the discovery of the relics by Saint Ambrose, the cult of Saints Gervasius and Protasius was spread in Italy, churches were built in their honor at Pavia, Nola and other places. In Gaul (modern-day France), Around the year 400 churches were dedicated to them, at Mans, Rouen and Soissons. At the Louvre in Paris, there is now a famous picture of the saints by Lesueur (d. 1655), which was formerly in their church, Saint-Gervais-Saint-Protais in Paris. According to the "Liber Pontificalis," Pope Innocent I (402-417) dedicated a church to them at Rome. Later, the name of St Vitalis, their father, was added to the title of this church (Basilica of San Vitale). Very early on, their names were inserted into the Litany of the Saints.