How the Holy Chalice came to València
The cup used by Jesus Christ at the Last Supper was brought from Jerusalem to Rome by St. Peter and used since then by him and the successive Popes of the Church in Rome in the Eucharistic celebrations until the year 258, when Pope Sixtus II, commissioned his deacon St. Lawrence to take the cup out of Rome to protect it from the persecution of Emperor Valerian.
St. Lawrence brought the relic to Huesca, where his parents lived. The chalice ended up hidden in the monastery of San Juan de la Peña and in 1399 it was given by the monks of the monastery to King Martin I of Aragón, from whom three letters insistently claiming the relic are preserved. Once in his hands, Martin I took the grail to the chapel of his residence in Zaragoza, the Palacio de la Alfajería. And another king, Alfonso the Magnanimous, moved the Holy Chalice in 1424 to the Royal Palace of Valencia, his residence at the time.
The conquest of the kingdom of Naples meant the Magnanimous had to undertake costly military campaigns for which he needed loans, one of which he contracted with the church hierarchy. The king backed him up with all his relics, including the Holy Chalice, which he had to hand over in 1437 to write off his debt to the church. It was preserved and venerated for centuries among the relics of the Cathedral, and until the 18th century it was used to contain the consecrated form in the "monument" of the Holy Thursday, until it was finally installed in the old Chapter House, enabled as the Chapel of the Holy Chalice in 1916.