Scientific testing at the Church of the Holy Sepulchre dates material there to the fourth century AD, supporting traditional views of the site's age. Tradition says that the church was built on the site of Jesus’s tomb 300 years after his death. Although it is still unknown whether the tomb genuinely held Jesus’s body after His crucifixion, National Geographic says that tests on the limestone bed reveal it was constructed around AD 345, shortly after the reign of Emperor Constantine. St Helena, the emperor’s mother, reputedly discovered the tomb around the year 327. When her son legalised Christianity, the Romans built a church over the tomb. Now, Antonia Moropoulou, chief scientific coordinator of the restoration works on the church, said testing was consistent with historical beliefs that the Romans built a monument on the tomb. "This is a very important finding because it confirms that it was, as historically evidenced, Constantine the Great responsible for cladding bedrock of the tomb of Christ with the marble slabs in the edicule," she said. The findings are especially noteworthy as, until now, the earliest architectural evidence found in the shrine dated it to no earlier than the Crusades. In October 2016, the tomb was opened for the first time in centuries at the start of delicate restoration work. Inside, scientists found an older marble slab incised with a cross. The results will be published in the Journal of Archaeological Science: Reports.