Alternate history, Aztec/Ottoman empires in 20th century (YA?) [Solved] [s]

[Benjamin]

The gist of it was that the Black Death had wiped out 3/4 of the population of Europe, rather than 1/4, and the Ottoman and Aztec empires had become superpowers. The male protagonist travelled from Europe to Mexico and later around North and South America. I think it was part of some sort of rebellion against one or both of the empires.

I read this in the late 90s but it was probably pretty old by then, I seem to recall it was set in the 1960s and I guess it was written then too.

[Moloch]

Could it be The Gate of Worlds?

[Justanotherbiblophile]

I'm betting _Crystal Empire_ 0-812-55425-6

But, protag(s) were refugees from Europe who had small (dying) settlement on NA coast. Traveled inland, however the main Aztec base? I'm betting was in SF, instead of the 'bay that was prone to earthquakes' == Gulf of Mexico.

Also, should note, that book is not really 'alternate history', but 'fantastic alternate history' since it has other things going on besides just a (plausible) historical turning point or two.

[Benjamin]

I don't think it was Crystal Empire, but Gate of Worlds sounds very similar. Thanks!