Here is what I got... Aztecs was conquer by Herman Cortes. He became rich by acquiring plantations and gold mine. The Incas were defeated by Franciso Pizzaro. The conquistador were motivated by their religious faith and by loyalty to their monarch. Hope this helped :)
<h2>They justify it with <em>''to preach God's word among them''.</em></h2>
Explanation:
Religion was the justification, but their motivation was the Gold and ''infinite wealth''. When first european arrive they saw that gold was everyone, but our natives didn't value that metal in an economical way, because they used it to worship gods.
But, the European point of view was Gold = Power. So, they enter in our lands seeking gold.