The three square league grant was made to three brothers-in-law. Jose Antonio Serrano was the son of Leandro Serrano, grantee of
Rancho Temescal. In 1838, José Serrano married Rafaela, daughter of
Rosario E. Aguilar, majordomo of San Diego Mission. Blas Aguilar (1811-1885), son of Rosario E. Aguilar, was majordomo at Temecula in 1834, and
alcalde of
San Juan Capistrano in 1848. With the
cession of California to the United States following the
Mexican-American War, the 1848
Treaty of Guadalupe Hidalgo provided that the land grants would be honored. As required by the Land Act of 1851, a claim for Rancho Pauma was filed with the
Public Land Commission in 1852, and the grant was
patented to José Antonio Serrano, Blas Aguilar and José Antonio Aguilar in 1871. Adelaida Serrano, daughter of José Antonio Serrano, married Judge
Benjamin I. Hayes (1815-1877) in 1866. Over the next two decades, parts of the ranch were sold, with one-third of the acreage going to Hayes' son, J. Chauncey Hayes, and another to
Thaddeus Amat, bishop of Los Angeles. In 1892, the ranch site was designated as part of the
Pauma and Yuima Reservation. ==Historic sites of the Rancho==