“Aztec” by Gary Jennings.

https://bookshop.org/p/books/aztec-gary-jennings/784861bf1a137811?ean=9780765317506&next=t

It’s a novel about coming of the Spanish.

I had to read it when I came across an article the author wrote. He wanted a word for ‘orange.’ He wanted to book to sound authentic, and the Americas didn’t have oranges. He ended up using jacinth