Aztec, by Gary Jennings also fits this category. Actually, I think he's
written several books along these lines. The novels of Edward Rutherford
(London, Sarum, the Forest) often include sections with culture contact as
a theme. And, if you want to take it really far back in time, Dance of the
Tiger (Bjorn Kurten), about the interaction between Cro Magnon and
Neanderthal, is a perennial favorite of mine.

R. Affleck