Establishing the US-Mexican border was done in two stages. The City first helped the Mexicans achieve their independence from Spain in 1821 by having the US and England give them a hand. The Mexican-American War of 1846 was the second stage. That’s when Lionel, Head of Mayer’s dynasty in the City, decided to get the US Congress to send an expedition of US troops to Mexico. It was a simple plan. Congress would send US troops to occupy Mexico City in order to force Mexico to relinquish its claims with regards to Texas and other parts of the south. The troops would remain there until the Mexicans cried uncle, and signed the Treaty of Guadalupe Hidalgo.
The treaty called for the U.S. to pay $15 million to Mexico and to pay off the claims of American citizens against Mexico up to $3.25 million. It gave the United States the Rio Grande as a boundary for Texas, and gave the U.S. ownership of California and a large area comprising roughly half of New Mexico, most of Arizona, Nevada, and Utah, and parts of Wyoming and Colorado. Mexicans in those annexed areas were ordered to be removed from their homeland unless they declared loyalty to the US government. Over 90% chose to pledge loyalty in exchange for not losing their homes.
The border keeping the French Catholics and the English Loyalists north of the 49th parallel was defined by the Oregon Treaty of 1846. After drawing a straight line along the 49th parallel in the north, and another along the Rio Grande extending to the Pacific Ocean in the south, the Manifest Destiny concept became a reality. America was a white, English-speaking and Protestant country from coast to coast, with Canada to the north and Mexico to the south. The US Spanish speaking population chose to become Americans, and the recalcitrant Indians were relocated on reserves.
In America, the first locomotive was built in 1830, but transportation remained limited to steam boats, canals, rudimentary roads and short rail systems east of the Mississippi. The Oregon Trail had become a very primitive way to go west after the Louisiana Purchase, but that didn’t favor California. Now that the Spanish administration and troops were on their way back to Spain, Lionel, head of the City banking dynasty, found the ideal way to populate California with ‘Americans’. He had been waiting for this moment to start a gold rush. He had known there was gold in California, and since the telegraph had been clicking away throughout America and Europe since 1844, it was just a matter of letting everybody know there was a lot of gold waiting to be picked up off the ground in California. Some 300 000 individuals moved in, easily displacing, when not massacring, the native populations, and overwhelming the Catholic Spanish speaking population. California went straight into statehood. As a bonus, close to 4000t of gold was produced, bought up, and stockpiled in the City’s vaults.