Mortar Found at “Jesus’ Tomb” Dates to the Constantine Era

The new analysis correlates with historical accounts stating that the tomb was discovered by the Romans, under the direction of emperor Constantine

The Church of the Holy Sepulchre's Edicule, a shrine that encloses Jesus’ purported resting place Michael Privorotsky CC 2.0

In the year 325 A.D., according to historical sources, Constantine, Rome’s first Christian emperor, sent an envoy to Jerusalem in the hopes of locating the tomb of Jesus of Nazareth. His representatives were reportedly told that Jesus’ burial place lay under a pagan temple to Venus, which they proceeded to tear down. Beneath the building, they discovered a tomb cut from a limestone cave. Constantine subsequently ordered a majestic church—now known as the Church of the Holy Sepulchre—to be built at the site.

Over the centuries, the Church of the Holy Sepulchre has been razed during regional conflicts, consumed by a fire and rattled by an earthquake—only to be resurrected after each catastrophe. Because of the church’s tumultuous history, experts have questioned whether the tomb was at some point removed or destroyed, reports Keir Simmons of NBC News. Previously, the earliest archaeological evidence found at the site of the tomb dated to the Crusader period, about 1,000 years ago.

Then, in 2016, the tomb was opened for the first time in centuries, when experts from the National Technical University of Athens began a much-need restoration of the Edicule, a shrine that encloses Jesus’ purported resting place. ​There, the team discovered the original limestone walls and a “burial bed,” or long shelf where Jesus’ body would have been laid after his crucifixion, according to Christian tradition.

The tomb was open for just 60 hours, during which time researchers took samples of mortar that had been sandwiched between the burial bed and a cracked marble slab adorned with a cross. Researchers thought the slab was likely laid down during the Crusader period, or perhaps not long before the church was destroyed by the Fatimid Caliph of Egypt in 1009, but they needed to test the samples.

Now, Kristin Romey reports in a National Geographic exclusive, that testing of mortar slathered over the limestone cave lends credence to historical accounts of the tomb’s discovery by the Romans. The mortar has been dated to approximately 345 A.D., which falls “securely in the time of Constantine,” Romey writes.

To test the mortar samples, researchers relied on optically stimulated luminescence (OSL), a technique that is able to determine the last time quartz sediment was exposed to light.  And the results suggested that the marble slab was in fact laid down during the Roman period, conceivably under the direction of emperor Constantine.

“Obviously that date is spot-on for whatever Constantine did," archaeologist Martin Biddle, author of The Tomb of Christ, an important text on the Church of the Holy Sepulchre, tells Romey. "That's very remarkable."

The project's chief scientific supervisor Antonia Moropoulou and her team will publish their complete findings on the samples in an upcoming issue of the Journal of Archaeological Science: Reports. The National Geographic Channel will also air a documentary titled "Secrets of Christ’s Tomb" on December 3.

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