For more than 400 years, the Northwest Passage through the Canadian archipelago was the holy grail of exploration. Though entirely above the Arctic Circle, its importance was that it might be a pathway between Europe and the riches of Asia.
By the 16th century, the Spanish and Portuguese had developed seaborne trade routes to the “Indies.” The Spaniards passed through the mid-latitudes of Mexico and Central America, then across the Pacific. Avoiding conflict, the Portuguese went south along the west coast of Africa and across the Indian Ocean. The navies of the two nations assured that other European merchants could not use these routes.
An alternative path was needed. By the mid-1500s, voyages of exploration supported by the English, French, and Dutch governments set out to find a Northern Hemisphere route to Asia. There were two possibilities: a passage to the northeast along the coast of Russian Siberia, or the fabled Northwest Passage through the Canadian archipelago. In both cases, the limiting factor was sea ice: Even in summertime, key parts of each passage were blocked.