Spanish and Mexican land titles in United States law: the guarantee of 1848 and the California commission of 1851

The treaty of 1848 bound the new sovereign to respect property "of every kind" already held in the ceded territories, and the act of 1851 ordered American commissioners and courts to decide land claims by "the laws, usages, and customs of the government from which the claim is derived" - that is, by Spanish and Mexican law. The same act put the burden on the holder: a claim not filed within two years became public domain.