The Sacred Nail of the Colle di Val D’Elsa, according to tradition, arrived in the town, valdelsano in the 9th century as a legacy of a French bishop, after having arrived in Italy through Saint Elena, mother of the emperor Constantine, who in 326 collected the four nails in Palestine. The relic was initially kept in the parish church in Piano and then later in the duomo, where in the 15th century a tabernacle was constructed containing the nail inside a barrel. The Sacred Nail is about 22 centimetres long and is bent in such a way from the point to form an L, on which has been inscribed the acronym INRI. Its particular shape suggests that it could have been used to nail the left foot of Jesus Christ to the cross. The Sacred Nail was jealously guarded and displaying it was very rigidly and formally regulated: it was displayed only on Holy Friday, whilst other exhibitions, which are mentioned in the manuscript of Beltramini, were only permitted on particular occasions, deliberated by the Council (in 1471, for example, on the occasion of the visit of the nephew of Pope Sisto IV). Preserved in the cathedral di Colle and kept in the tabernacle built by Mino da Fiesole, the relic is today carried in an annual process during the Festival of the Sacred Nail, which takes place the second Sunday of September.

Source: ecomuseovaldelsa.org