Historical evidence for the past existence of a burial crypt in the church of St Mary Magdalene in Rennes-le-Château lies in the form of an old parish register relating to the years 1694 to 1726 (the burial crypt was also referred to as the Tomb of the Lords) quotations from this parish register were given in Captier and Corbus 1985 book, LHéritage de LAbbé Saunière.
They cited a reference found in the parish register to the death of Dame Anne Delsol, in 1705:
In the year one thousand seven hundred and five, on the thirtieth day of March, the death occurred, in the castle of Rennes, of Dame Anne Delsol, aged about 75 years, widow of Monsieur Marc Antoine Dupuy, of Pauligne, former treasurer of France and of the Généralité [treasury subdivision of old France] of Montpellier she was interred on the thirty-first day of the said month, in the village church, in the Tomb of the Lords, which is next to the Baluster
They also cited a reference found in the parish register to the death of Monsieur Henry du Vernet, in 1724:
In the year one thousand seven hundred and twenty-four, on the twenty-fourth day of October, at Rennes, in the diocese of Alet, the death occurred of the noble gentleman Henry de Vernet, lieutenant colonel of cavalry in the regiment of Ruftège, who, having received the last rites, was buried in the village church, in the Tomb of the Lords
When Jacques Cholet excavated beneath the Church during the late 1950s and early 1960s, he wrote in his Report dated 25 April 1967 (Results of the researches):
On my own account I excavated both under and behind the altar but found nothing. I also excavated in line with and in front of the altar again nothing / I was also made to tear up the floor of the church, starting from the pulpit: my sponsor, a pendulum enthusiast, had located the entrance of the underground passageways there but we found nothing. I persevered as far as the foundations of the church, digging as far as virgin soil. We found the outline of numerous empty vaults. We resumed the same task along the south wall, with approximately the same result, the only difference being that all the human remains, which were missing on the other side, had been placed there higgledy-piggledy. On the advice of a female clairvoyant we were urged to excavate behind the Altar but found nothing / With Mr. Domergue and his friends we dug an approach trench about 18 metres long through solid rock, starting from his property. Mr. Domergue was convinced that the entrance to the underground passages was near the Altar, but the approach trench got as far as the area underneath the altar and we found nothing.