Along the right side of the nave, in a niche inserted into the wall, are some relics of Saint Catherine.
The term relic (from the Latin reliquus = remained) means what is left of the body of persons who have been recognized as possessing extraordinary virtues of holiness. Over time the term has been extended also to the clothing and objects that came into direct contact with Saints.
The veneration of relics emerged as a practice from the earliest times of Christianity and takes its origin from the fact that God became man, leaving concrete traces of His life on earth. This practice was extended later to the relics of Saints, considered ‘other Christs’ whose remains were preserved. The golden age for the veneration of relics was the Middle Ages: the presence of relics meant, for the town or shrine that possessed them, prestige and protection, besides making them important pilgrimage sites.
The niche holds Catherine’s thumb, preserved inside a crystal and silver reliquary. For the festivities in honor of the Saint which are celebrated every year, the reliquary is carried into Piazza del Campo and used to bless Italy and Europe, of which Catherine is Patron Saint.
The niche also contains some objects which came into contact with the Saint: the chalice with which she received the Eucharist from Jesus, the ropes she used to discipline herself three times a day, and the sacred stone to be placed on the portable altar so that wherever she was, a priest could celebrate Holy Mass and administer the Sacraments to her. It seems that the blood of Thomas Becket spattered this stone when he was murdered in Canterbury Cathedral, where Catherine went on a pilgrimage.
In the center of the niche is the bust made of embossed bronze in which the Saint’s head, the most important of her relics, was first kept. Now it is in the nearby chapel.