Before the 1500s, who and what were the final authorities with regard to most knowledge?

Writing assignment: excitement, expansion, changing horizons it would be if you could give me some credible websites that i can use to finish my assignment : ) 1) use the internet or other resources to research the aztecs and their relationship to cortes; and the incas and their relationship to pizarro. 2) explain how the aztecs and cortes interacted with each other, and what happened as a result of their meeting. also, explain how the inca and pizarro interacted with each other, and what happened as a result of their meeting. 4) analyze the impact each explorer (cortes and pizarro) had on the people he conquered, by explaining how the economy and the lives of the people changed. 5) explain how spain profited from these voyages. -you don't have to do all of em just give me as much as you can you < 3