Anderson, Poul. "Eutopia"
Divergence: c 732 CE
What if: Alexander the Great lived longer or Christianity fell before Norse, Arab and Magyar attacks.
Summary: A crosstime explorer from an advanced Alexandrine timeline violates a taboo while visiting a Norse-Magyar North America.
Published: In Dangerous Visions (ed. Harlan Ellison), Doubleday 1967, NAL 1975, ibooks 2002 (0743452615BUY); Past, Present, and Future Perfect: A Text Anthology of Speculative and Science Fiction (eds. Jack C. Wolf and Gregory Fitz Gerald), Fawcett 1973; The Dark Between the Stars, Berkley 1981; Past Times, Tor 1984 (0812530810); and The Best Alternate History Stories of the 20th Century (eds. Harry Turtledove and Martin H. Greenberg), q.v.
Original in: English.
Translation: French by France-Marie Watkins as "Eutopia", in Dangereuses Visions (ed. Harlan Ellison), J'ai lu 1975.