Cologne's location on the River Rhine placed it at the intersection of the major east-west trade routes and this was the basis of its wealth and power. Besides its economic and political significance, Cologne also became an outstanding centre of medieval pilgrimage when Cologne's archbishop gave the relics of The Three Wise Men to the Cathedral in 1164. In the Middle Ages it was the most densely populated and one of the most prosperous towns in the German-speaking region, with an established university and membership of the Hansa alliance (Hanseatic League) of trading cities. This economic association of towns and cities stretched from the Baltic to the North Sea and dominated trade along the coast of Northern Europe for centuries. Trade fairs, which provided early printers with a market for their books, were an established feature of Cologne life.