Analysis of information sources in references of the Wikipedia article "Pope Leo I" in English language version.
We find him, [Dioscorus] ... in correspondence with pope Leo the Great, who gave directions, as from the see of St. Peter, to the new successor of St. Mark; writing, on June 21, 445, that "it would be shocking (nefas) to believe that St. Mark formed his rules for Alexandria otherwise than on the Petrine model" (Ep. 11)This article incorporates text from this source, which is in the public domain.