Justin Martyr in the 2nd century explicitly noted and identified them as "demonic imitations" of the true faith, and that "the devils, in imitation of what was said by Moses, asserted that Proserpine was the daughter of Jupiter, and instigated the people to set up an image of her under the name of Kore" ("First Apology"). Through the 1st to 4th century, Christianity stood in direct competition for adherents with the mystery schools, insofar as the "mystery schools too were an intrinsic element of the non-Jewish horizon of the reception of the Christian message". Beginning in the third century, and especially after Constantine became emperor, components of mystery religions began to be incorporated into mainstream Christian thinking, such as is reflected by the disciplina arcani.