On 9 December 1853, in the catacomb of Praetextatus on the Appian Way, excavators found the tomb of a young woman sealed with a marble tablet reading, in Latin, 'to the soul of the innocent and pure Vibiana', with a laurel wreath — taken then as the sign of a martyr. In Rome her relics were given to Thaddeus Amat, newly named bishop of Monterey in California, who brought them to Santa Barbara in 1855 and later enshrined them in his cathedral of St. Vibiana in Los Angeles. She is the patroness of the Archdiocese of Los Angeles, and since 2002 her relics have rested in a marble sarcophagus in the mausoleum of the new cathedral. Nothing is known of her beyond the tablet.
In 1941, after Archbishop John Cantwell of Los Angeles visited the basilica at Guadalupe, the Archbishop of Mexico City gave his archdiocese a small fragment of St. Juan Diego's tilma — the cloak on which the image of Our Lady of Guadalupe appeared in 1531. Since 2 September 2012 it has been kept in a golden reliquary in the heart of a bronze statue of St. Juan Diego, in the cathedral's Chapel of the Tilma, beneath a mosaic of Our Lady of Guadalupe.
What is not claimed here: how the fragment was taken from the tilma and authenticated is not documented in any source this entry could reach, and Vibiana's martyrdom is inferred from the wreath on her tablet, not recorded.