Trade with the Far East and China (silk, spice etc) blocked or controlled by Russia and Turkey (after fall of Constantinople). Spain and Portugal are at the wrong end of the Mediterranean . Access to what trade is allowed through is largely mediated by Venice. There is therefore potential profit in finding a route South around Africa and establishing direct trade links with the East. In this, at least, Spain and Portugal's position at the Western edge of Europe is an advantage since they can exercise some control over the Straits of Gibraltat and any attempt to replicate their successes in Africa. (See Prince Henry the Navigator, Bartolomeo Diaz and Vasco da Gama.) In exploring down the West Coast of Africa Portugal discovers and colonises Madeira and the Azores; Spain , the Canaries, giving both of them footholds and way-stations for later passages across the Atlantic. (See Columbus, and Magelllan). There was also major support for these ventures from the Church who saw in them a way of taking Christianity around the world.