"Archetypes" (also known as "Etos Kosmou 6825") is an alternate history short story by Harry Turtledove, first published in Amazing Stories, November, 1985. It is a story set in the Agent of Byzantium series, and was reprinted in the fix-up novel of the same name in 1987. It has also been reprinted in The Way It Wasn't: Great Science Fiction Stories of Alternate History (Carol Publishing, 1996), edited by Martin H. Greenberg and Robert Silverberg.
It is 1316 and the Persians are trying to sow discord in Mesopotamia. Hundreds of posters appeared overnight in the town of Daras advocating Nestorians and Monophysites to rise up against the oppression of the orthodox faith and change their allegiance to the King of Kings. It would have taken dozens of scribes to produce this many posters but no sign of a conspiracy this large existed. Basil Argyros was sent to investigate.