Contrary to the Treaty of Guadalupe Hidalgo, which guaranteed full protection of all property rights for Mexican citizens, it placed the burden on landholders to prove their title.
The expense of the long court battles required many land holders to sell portions of the property or even trade it in payment for legal services.
The Act required all holders of Spanish and Mexican land grants to present their titles for confirmation before the commission.
It then consisted, by appointment of President Millard Fillmore, of Hiland Hall, Harry I. Thornton, and James Wilson as commissioners.
[7][2]: 102 American officials acquired the provincial land records of the Spanish and Mexican governments in the capital at Monterey.
[8][9] The new state's leaders soon discovered that the Mexican government had given a number of grants to Californios just before the Americans gained control.
The Mexican governors had rewarded faithful supporters and hoped to prevent the recent American arrivals from gaining control of the land.
Land had until the gold rush been of little value and boundary locations were often quite vague, referring to an oak tree, a cow skull on a pile of rocks, a creek, and in some cases a mountain range.
[10] The confirmation process required lawyers, translators, and surveyors, and took an average of 17 years (including the Civil War, 1861–1865) to resolve.
This resulted in additional pressure on Congress, and beginning with Rancho Suscol in 1863, it passed special acts that allowed certain claimants to pre-empt their land without regard to acreage.
[15] Juana Briones,[16] whose early life started with her selling milk in Yerba Buena (today San Francisco), became the owner of Rancho La Purísima Concepción in Santa Clara County.
[18] Article X[19] of the Treaty of Guadalupe Hidalgo, drafted by Bernardo Couto, Miguel Aristáin, and Luis Cuevas, was intended to protect the land grants made during the Spanish and Mexican administrations in Alta California.
[citation needed] One of the more significant sets of claims was filed on February 19, 1853, on behalf of the Roman Catholic Church by Archbishop Joseph Sadoc Alemany, wherein he sought the return of all former mission lands in the State.