Between 1803 and 1854, the United States achieved a vast expansion of territory through purchase (Louisiana Purchase), negotiation (Adams–Onís Treaty, Oregon Treaty), and conquest (the Mexican Cession). Of the states carved out of these territories by 1845, all had entered the union as slave states: Louisiana, Missouri, Arkansas, Florida, and Texas, as well as the southern portions of Alabama and Mississippi. With the conquest of northern Mexico, including California, in 1848, slaveholding interests looked forward to the institution flourishing in these lands as well. Southerners also anticipated annexing as slave states Cuba (see Ostend Manifesto), Mexico, and Central America (see Golden Circle (proposed country)). Northern free soil interests vigorously sought to curtail any further expansion of slave soil. It was these territorial disputes that the proslavery and antislavery forces collided over.