Over a hundred years passed after Magellan's discovery before the Spanish occupied the area. In 1668 missionary activity was initiated and, after first meeting with every success, aroused an opposition that led to open revolt against the priests and the Spanish troops. Sporadic conflict continued until 1694, when, as a last measure, the inhabitants of all the islands were transported to either Guam or Saipan. Those on Saipan were removed to Guam in 1698. War, famine, and disease so reduced the Chamorros during the first three centuries of Spanish control that, of the original population, estimated between 40,000 and 90,000, only 3760 remained in 1710, the year of the first census. By 1764 the number was 1654. The islands were generally known by this time as the Marianas, having been renamed in honor of the Spanish Queen, Maria Anna, widow of Henry IV and patroness of the first missionaries.
Long before the beginning of missionary activity in the Marianas, Guam became a supply station for Spanish galleons plying between Acapulco, Mexico, and Manila in the Philippines. The ships, only one a year during the early colonial period, were dispatched from New Spain in February, and, taking advantage of the trades, made the reckoned 70-day journey to Guam without altering their sails, and arrived in the Philippines before the beginning of the westerly monsoon. Guam, the only stop along the route, supplied fresh water, and equally important in those days of scurvy-plagued ocean travel, fresh vegetables and fruits, which were obtained by barter with the natives. This early importance as a way station, beginning before Spanish occupancy, increased as trade expanded in the Pacific, and reached an apex during the whaling period.
The economy of the Marianas did not rise much above the subsistence level during the entire Spanish period. The small Spanish population consisted largely of administrators, soldiers, and churchmen. Native farms supplied food, the seas a limited catch. Probably the major economic advantage of Spanish rule was the introduction of domesticated animals and new vegetables and fruits. There was also acceptance by the natives of certain Latin cultural patterns.
After the Spanish American War Guam was acquired by the United States under the terms of the Treaty of Paris, December 10, 1898. The island was already in our possession, having been captured almost incidentally in the previous summer. Because of the slow communication, the Spanish governor had not learned that a state of war existed, and he was surprised to learn that the American cruiser in the harbor was not saluting the port. Hard pressed financially, Spain sold the remaining Marianas and the Carolines to Germany for $4,500,000 in 1899.