Financing real estate in California undoubtedly started long before any record of it. Even for highly civilized societies in prehistoric and, even early historic periods, most history focuses on war, rulers, and social trends, not everyday business life. One early type of money was dentalium shells, small tubular molluscs that look like little unicorn horns. While this species lives throughout California, they live partly buried in the sand in deep water. California was a largely neglected and ignored dependency of Spain for around a hundred years before the founding of the Missions there. Spain moved into Alta California in 1769 to protect the silver mines of northwestern New Spain from a feared Russian or English advance. The Mexican War ended quickly, by concession of California to the United States by the Treaty of Guadalupe Hidalgo, February 2nd 1848. This was a generous settlement asking only that the citizens acknowledge the US government.