Das geheime Markusevangelium

In 1973, Morton Smith published the excerpt from a letter from Clement of Alexandria, in which there are two quotes from a hitherto unknown Gospel of Mark. Is this a new source for the historical Jesus, a patchwork of reminiscences of the canonical gospels or even a fake? In dealing with previous research, the author explains to what extent we have here a highly interesting document about the coexistence and confrontation of church Christianity and Christian Gnosis in Alexandria in the 2nd century.