I was listening to Dan Carlin's podcast about the topic and it gave me a whole new perspective on the topic, although didn't answer the question.
Conquering such vast land even across the sea in such a short time with all the lootings and the slaves surely must have seen numinous by the people around.
Was it considered a genocide?
I'm running a bit late, but you might enjoy this older answer from /u/Libertat that touches on the subject.