The article, after a brief discussion about the theological idea of Christian martyrdom, outlines a short history of the Church approval of martyrdom between Late Antiquity and Early Modern age. Then it focuses the fact that only during the Seventeenth century all the canonization procedure reached a definitive formalization, which was completely fixed in the De servorum Dei beatificatione et beatorum canonizatione, written by Prospero Lambertini, the future pope Benedict 14th, where was precisely defined also the juridical-historical idea of Catholic martyrdom. The future pope thought that, in general, also the martyrdom could be proved through a special kind of juridical trial, based upon the canon law: so the deaths of the martyrs had t...