Simak, Clifford. The Fellowship of the Talisman
Divergence: c 500 CE
What if: A series of "blights" periodically prevented Europe from advancing beyond the Dark Ages. Also, magic works.
Summary: A young man accompanies a woman and her griffin on a quest to retrieve a talisman to fight the blight.
Published: Ballantine/Del Rey 1978 (0345277511), 1981 (0345300475), 1987 (0345339576).
Original in: English.
Translation: German by Jürgen Saupe as Die Bruderschaft vom Talisman, Goldmann 1987 (3442233305).
Translation: Italian by Roberta Rambelli as La compagnia del talismano, Libra 1979.
Translation: Portuguese by Eurico Fonseca as A Irmandade do Talismã, Livros do Brasil 1980.