Researching the truth about saints could be dangerous. More than once the Acta Sanctorum would question the historical foundations of a popular cult or a venerable tradition. The worst incident occurred when Papebrochius expressed his doubts about the Carmelite tradition according to which the prophet Elijah was the founder of their religious Order. The Carmelites managed to have the Acta Sanctorum condemned by the Spanish Inquisition in 1695 (a condemnation lifted by Rome in 1715). – On another occasion a treatise on the authenticity of ancient charters published by the same Papebrochius in the Acta Sanctorum of April (1675) and illustrated by superb facsimiles was criticized by the French Maurist monk Mabillon in his masterwork De re diplomatica (1681).