Alcatraz Island later invalidated the sale and paid Frémont nothing. Frémont and his heirs sued for compensation during protracted but unsuccessful legal battles that extended into the 1890s. Following the acquisition of California by the United States as a result of the Treaty of Guadalupe Hidalgo (1848) which ended the Mexican–American War, and the onset of the California Gold Rush the following year, the U.S. Army began studying the suitability of Alcatraz Island for the positioning of coastal batteries to protect the approaches to San Francisco Bay. In 1853, under the direction of Zealous B. Tower, the United States Army Corps of
Occupation of Alcatraz Occupation of Alcatraz The Occupation of Alcatraz was an occupation of Alcatraz Island by 89 American Indians and supporters, led by Richard Oakes, LaNada Means, and others. They chose the name Indians of All Tribes (IOAT) and John Trudell was the spokesperson. According to the IOAT, under the Treaty of Fort Laramie (1868) between the U.S. and the Lakota, all retired, abandoned or out-of-use federal land was returned to the Native people who once occupied it. Since Alcatraz penitentiary had been closed on March 21, 1963, and the island had been declared surplus federal property in 1964, a number of