New Mexico, when acquired, contained one of the oldest towns on the continent, and a considerable population of Spanish origin. California, almost simultaneously with her acquisition, was peopled in the course of a few months by the world-renowned gold discoveries. Very unexpectedly, therefore, to politicians of all grades and opinions, the slavery question was once more before the nation in the year 1850, over the proposition to admit both to the Union as States. As the result of the long conflict of opinion hitherto maintained, the beliefs and desires of the contending sections had by this time become formulated in distinct political doctrines. The North contended that Congress might and should prohibit slavery in all the territories of the Union, as had been done in the Northern half by the Ordinance of 1787 and by the Missouri Compromise. The South declared that any such exclusion would not only be unjust and impolitic, but absolutely unconstitutional, because property in slaves might enter and must be protected in the territories in common with all other property. To the theoretical dispute was added a practical contest. By the existing Mexican laws slavery was already prohibited in New Mexico, and California promptly formed a free State constitution. Under these circumstances the North sought to organize the former as a Territory, and admit the latter as a State, while the South resisted and endeavored to extend the Missouri Compromise line, which would place New Mexico and the southern half of California under the tutelage and influence of slavery. These were the principal points of difference which caused the great slavery agitation of 1850. The whole country was convulsed in discussion; and again more open threats and more ominous movements towards disunion came from the South. The most popular statesman of that day, Henry Clay, of Kentucky, a slaveholder opposed to the extension of slavery, now, however, assumed the leadership of a party of compromise, and the quarrel was adjusted and quieted by a combined series of Congressional acts. 1. California was admitted as a free State. 2. The Territories of New Mexico and Utah were organized, leaving the Mexican prohibition of slavery in force. 3. The domestic slave-trade in the District of Columbia was abolished. 4. A more stringent fugitive-slave law was passed. 5. For the adjustment of her State boundaries Texas received ten millions of dollars. [Sidenote: Greeley, "American Conflict," Vol. I., p. 208.]