Silverberg, Robert. "Looking for the Fountain"
Divergence: c 1150 CE
What if: A shipload of Crusaders was blown off course and ended up in Florida.
Summary: While looking for the Fountain of "Youth", Ponce de Leon finds a tribe of Christian AmerInds who want to sail to Palestine and free Jerusalem.
Published: In Isaac Asimov's Science Fiction Magazine, May 1992 and What Might Have Been? Volume 4: Alternate Americas (eds. Gregory Benford and Martin H. Greenberg), q.v.
Original in: English.
Translation: French by Patrice Duvic as "Jouvence", in Futurs pas possibles (ed. [[ed. unknown]]), Presses Pocket 1991 (226604270X).