The best replacement for incas is aztecs.

The best alternatives to incas are rated as following:
★★★★★  aztecs
★★★★  mayans
★★  spaniards
★  conquistadors
★  mayas
★  incans
★  pizarro
  mayan
  incas
  conquistadores
  aztecas

Your alternative for incas is not listed? Suggest!
Speaking about incas, one probably shouldn't forget about pizarro.

Other search terms related to incas and their ratings are:
★★★★★ pizarro
★★ aztecs
You have in mind a companion for incas and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of incas in all years. Click on graph for more.
incas
aztecs
mayans