PORTUGAL is a narrow region with navigable rivers flowing westward and a long coast indented by fine harbors. Such a country seems fashioned to breed men for the sea. It was from her ports that the Arabs, after the Northmen the boldest of mediæval mariners, had made their explorations when the Moors held sway. The tradition of their voyages and of the new lands which they had discovered -- the Madeira and Cape Verde Islands -- lingered to redound to the glory of her harbors in later days.
The dawn of the fifteenth century found Portugal once more Christian and independent. By the valor of her arms she had expelled the Moor and had stopped the ambitious aggressions of Spain. She was quick with the old spirit of the Crusades. The Faith had blessed her sword and had given her power among the nations. The aggrandizement of that power was therefore to the Portuguese a mission hardly less sacred than that of spreading the Faith.
Hostile Spain, lying east and north of her, blocked her from land communication with Europe. Already Portuguese commerce with England, Flanders, and Germany had made a virtue of necessity and had been successfully carried on by sea. The accomplishment of both her sacred missions, then, must be by way of the sea.
164 The Cross-staff, from John Seller, Practical Navigation, London, 1680