The Rite of the Nivola is a Catholic liturgical rite as well as a historical reenactment that is celebrated yearly in the Duomo (Cathedral) of Milan, Italy; the tradition dates back to the 16th century and was initiated by Carlo Borromeo. It is a celebration of the "Santo Chiodo", purportedly a nail from the True Cross, which is regarded as the most important relic owned by the Archdiocese of Milan. The relic is also known as the "Santo Morso", as it is in fact shaped in a way that may resemble a part of a bridle. It is preserved in the apse of the Cathedral, in a case inside a tabernacle, about 45 m above the ground.