The Basilica of Santa Croce in Gerusalemme holds the most important collection of Passion relics in the West attributed to the empress Helena, mother of Constantine. Its reliquary chapel displays three fragments venerated as pieces of the True Cross, one of the nails, two thorns from the Crown, and the Titulus Crucis, the wooden title-board that named the crucified as "Jesus of Nazareth, King of the Jews" in Hebrew, Greek and Latin. The church itself was created in the fourth century inside a hall of the Sessorian palace, where soil brought from Jerusalem was placed so that pilgrims might venerate the Cross on "Holy Land" ground, giving the basilica its name. Because these are among the best-documented Cross relics and are gathered in one custodial church, they serve as the principal corpus for the fragmentary True Cross tradition scattered across Christendom.
Tradition credits Helena, mother of the emperor Constantine, with discovering the True Cross in Jerusalem around 325 CE during a pilgrimage to the Holy Land, and the relics now venerated at the Basilica di Santa Croce in Gerusalemme in Rome, wood fragments, an iron nail and two thorns, are traditionally associated with that discovery and with Helena's own foundation of the church to house them.