For more than 1,500 years Catholics have made pilgrimage to Rome's Santi Apostoli Church to venerate two apostles, St. Philip and St. James the Younger - who is said to have been Jesus' brother.
Bones believed to belong to the martyred saints are enshrined at the basilica and each encasing bears the name of the saint.
But now archaeologists say skeletal fragments enshrined at the church are too recent to have come from the time of Jesus Christ.
St. James, or James the Less, is purported to have been stoned to death or crucified in the Egyptian city of Ostrakine in about 60 AD - making the femur to new to have belonged to the saint.
It's not clear where the bones came from, or who moved them, but they've been housed in Santi Apostoli since it was constructed in the sixth century.
According to the Catholic belief, James the Less was killed around 60 AD.
That would make the bone some 160 years too recent to belong to the apostle.
'We consider it very likely that whoever moved this femur to the Santi Apostoli church, believed it belonged to St. James,' said Kaare Lund Rasmussen, a professor of archaeometry at the University of Southern Denmark.
Archaeometry is the application of chemistry and other scientific principles to determine the age of archaeological specimens.
'They must have taken it from a Christian grave, so it belonged to one of the early Christians, apostle or not, Rasmussen added.
'Though the relic is not that of St James, it casts a rare flicker of light on a very early and largely unaccounted for time in the history of early Christianity,'
Unfortunately a tibia and foot bone supposedly belonging to St. Philip were too contaminated to be dated, the researchers said.
The fate of Philip not entirely known: Though it's largely agreed he died around 80 AD, possibly in Hierapolis, Turkey, some accounts say he was crucified upside down.
Other maintain he beheaded, stoned to death or even died of natural causes.
Conjecture about Jesus having a biological brother named James comes from a variety of sources, though the relationship is not officially recognized by the Catholic Church.
The New Testament refers to various apostles—including James, Judas, Joseph (Joses) and Simon—as 'brothers' of Jesus, and mentions unnamed 'sisters,' as well.
But Catholic leaders have held the use of brother or sister, especially in the original Greek, refers to a close confidant.
Some scholars have argued they could have been half-siblings from a previous marriage of Mary's or Joseph's or even nieces and nephews on either side.
The Catholic Encyclopedia references apocryphal writings that claim Joseph had a previous wife, named Melcha.
'They lived 49 years together and had six children, two daughters and four sons, the youngest of whom was James (the Less, 'the Lord's brother').'
According to the apocrypha, a year after Melcha died, 90-year-old Joseph was betrothed to Mary, who was only 13 or 14 at time time.
'A miracle manifested the choice God had made of Joseph, and two years later the Annunciation took place.'
A fifth-century Gnostic manuscript known as the 'First Apocalypse of James,' describes Jesus' secret teachings to James, whom he frequently refers to as 'my brother.'
At the same time, in the text, considered heretical, Jesus describes his disciple as 'not my brother materially.'
The James Ossuary, a first-century chest for housing remains, bears the inscription 'James, son of Joseph, brother of Jesus' on one side.
The inscription is considered significant because it may provide archaeological evidence of Jesus, as well as the possibility he had siblings.
The existence of the ossuary was announced in 2002, but its authenticity was immediately challenged.
The box's owner was charged with forging part of the inscription and while he was found innocent seven years later, the judge said the acquittal 'does not mean that the inscription on the ossuary is authentic or that it was written 2,000 years ago'.
In the early centuries of the Catholic church, martyrs' remains were often moved to shrines or churches, in a process called translation.
The earliest known example is in AD 354, when the remains of Saint Babylas were transferred from a cemetery in Antioch, Syria, to a church built especially to hold them a few miles away.
Santi Apostoli was partially destroyed by an earthquake in 1348 but rebuilt by Pope Martin V in 1417.
The tomb of Pope Clement XI, who oversaw major renovations to the church in the 18th century, is located in the basilica.
It also temporarily housed the tomb of Michelangelo before it was relocated to the Basilica di Santa Croce in Florence.
This article has been adapted from its original source.
© Associated Newspapers Ltd.