My knowledge of the Age of Discovery is assembled from a loose collection of stuff I learned in school and the odd passages in other books. Thinking about it, there are still a few points I'm confused on where things don't seem to make sense. If anyone has an answer or can point me to a good source I would be grateful.

The story I got in school was that the Portuguese were looking for a route to India. However, they spent decades content with the west coast of Africa and Vasco da Gama's initial voyage to India didn't set sail until years after Columbus' return. What Africa did have at this time was a profitable network of trans-Saharan trade routes that ran between Timbuktu in the Malian Empire to coastal cities in Algeria and Libya, and even as far as Egypt. Gold and slaves went out, salt came in. First question: were the Portuguese exploring the African coast as a way to cut out the middleman?

Now for Columbus. He'd been trying to get funding for a westward voyage before any other sea route to Asia was active, and in fact before Dias even rounded the Cape of Good Hope. As far as I know at that time the only claim of a circumnavigation of Africa had been made over 2,000 years earlier by the Phoenicians. So Columbus was in effect saying that the westward route would be more promising than attempting to sail around Africa. I realize that Columbus did some funny math to try and prove that a westward expedition was even feasible, but what gave him the confidence that it was the best choice? Were there any stories of land masses between Europe and Japan that Columbus would have known about? Did he know of Viking expeditions? Were there perhaps rumors that the ancients reached the Antilles?

Finally, I'm curious about the geopolitics involved in Spain actually funding the trip. In 1492, Spain finally wrapped up the Reconquista. And after wrapping up this 200+ year project they throw money at an Italian adventurer with visions of grandeur? Were they so eager for a prestige project? Columbus used funny math, but surely someone at the Spanish court could have called him on it. Spain had 3 universities by this point. Were they just too afraid of missing out on a potential opportunity and worried a rival might get it first?