Spanish historians Margarita Torres and José Ortega del Río believe a 2,000-year-old chalice is the Holy Grail, now hundreds of people have now flocked to see it in Leon, Spain.
The authors of the book 'Kings of the Grail' claim the cup was used by Jesus Christ at the Last Supper which was given as a gift to Spanish King Fernando I by a Muslim ruler.
Their studies led them to identify a part of the princess's goblet and a missing fragment as described in the parchments.
The director of the basilica's museum, Raquel Jaén said the cup was taken off display to find a location that could hold larger crowds.
"It was in a very small room where it was not possible to admire it to the full," she told AFP.
The historians said that the two Egyptian parchments they found in 2011 at Cairo's University of Al-Azhar set them on an investigation debunking some of the 200 supposed Holy Grails around Europe too.
The twelfth-century cup was donated by one of the five children of Ferdinand I to the Basilica of San Isidoro de León in Spain, where it remains.