In the several hundred years of European presence in the New World, Mexico only ruled California for 9 years.
The Pope has a stronger claim to California than does Mexico.
"In the several hundred years of European presence in the New World, Mexico only ruled California for 9 years."
I get 25 years: 1821 to 1846.
1821 = Mexican Independence from Spain (including California)
1846 = Declaration of Independent California Republic (June 10, 1846)