The term ‘legend’ originally refers simply to ‘matter that must be read – or heard’, which at the same time indicates the importance of this kind of stories.They assert a strong claim to their truth, and therefore constitute an indispensable addition to all that was already reported in the Bible through God's own words. Since they relate events from the new – and last – historical era, commencing with the birth of Christ, they form a continuation of the history of salvation.

Achim Masser (1976) distinguishes between the legends of Biblical origin and the legends of martyrs and saints. In his Bibel- und Legendendichtung des deutschen Mittelalters Masser is, in fact, applying, on the one hand, a broad concept of legend, including in its domain all subject-matter that professes to complement the story of the Bible, but on the other hand, a narrower concept is also applied, restricting the term legend to the story of a saint or martyr whose feast is celebrated by the Church, and which gives occasion to a reading of the story of his life, including the miracles attached to him. Masser distinguishes two situations of reception for the legend: the first is the holy mass in which, on the occasion of saints’ feasts, a summary version of the appropriate vita is read. The second is the refectory of the convent or monastery, where there is room for listening to much more detailed versions during the meals. The stories, gradually increasing in scale, profess to convey ‘truth’ and must have had a status similar to God's own word.

As to their intention and audience, a distinction should be made into three types of legend: the legends in the apocryphal gospels of the earliest period (e.g. the Gospel of Nicodemus), the early legends of martyrs (the so-called passiones from the first centuries of Christianity) and the later legends of saints. Whereas the apocryphal story-telling of the early days of Christianity demands a place alongside the canonical gospels as authentic Word of God, the other two types must be viewed as consciously non-biblical, but truthful and therefore authoritative additions to the Scriptures.