Spain claimed the entire Pacific Northwest, based on the Papal grant of 1493, and confirmed when in 1774 and 1775, Spanish explorers sailing north from Mexico became the first Europeans to explore, land, and establish claim to the Pacific Northwest.
Years later, the Spanish, disturbed by news of vessels from Britain, Russia, and the United States sailing in territory they considered their own, sent an expedition to establish a settlement and fort at Nootka Sound. Spanish naval officer Estevan Jose Martinez arrived at Nootka on May 5, 1789, and put his crews to work immediately building a fort and setting up facilities for a permanent settlement. He soon encountered vessels of other nations, including those of the British captain John Meares.
Later that year, the he and his crew captured four British trading vessels associated with Meares. Meares complained to the British government and Britain threatened war. Spain was militarily weak and ultimately acceded to British demands.
The Nootka Convention acknowledged that each nation was free to navigate and fish in the Pacific and to trade and establish settlements on unoccupied land.