The patron saint of Pavia is Saint Siro, who lived in the first half of the 4th century, founder of Pavia's first Christian community and its church: his body was kept for over six hundred years in the church of Santi Gervasio e Protasio, the city's oldest according to the chronicler Opicino de Canistris, founded in the Roman era.
One of Pavia's oldest traditions is the Feast of the Holy Thorns, which falls the day after Pentecost: on that occasion, the three thorns kept in the cathedral are carried in procession through the city, believed to be part of the crown placed on Christ's head during the Passion. The relics were originally part of the collection gathered by the Visconti in the chapel of the Visconti Castle, and were transferred to the cathedral in 1499, when, after the fall of Ludovico il Moro, it was feared they might be seized by the French.
Pavia remained capital of the Kingdom of Italy even in the Carolingian and Ottonian eras: in the basilica of San Michele Maggiore, Berengar of Friuli and his successors were crowned kings of Italy, up to Frederick Barbarossa in 1155, who resided there for thirteen years in various periods during the struggles against the Lombard League.
