Mexico into the acknowledgment of the Rio Grande as the boundary of Texas, but also to acquire further territory for the purpose of creating additional slave States. As soon as this impression, or suspicion, got abroad, the effect was an anti-slavery revival which enlisted the feelings and influenced the political action of many who had never sympathized with the Abolitionists, and of many who had steadily opposed them. These men came from both the old political parties, but the larger number from the Whigs. Indeed, during almost the entire period of the anti-slavery agitation by the Abolitionists, there had existed a body of men in the Whig ranks who were profoundly impressed with the evils of slavery, and who yet thought they could be more influential in checking its progress by remaining in their old party, and, in many sections of the country, maintaining their control of it. Of these men, John Quincy Adams stood undeniably at the head; and with him were associated, in and out of Congress, Mr. Seward, Mr. Benjamin F. Wade, Mr. Fessenden, Mr. Giddings, Mr. Thaddeus Stevens, besides a large number of able and resolute men of less public distinction, but of equal earnestness, in all parts of the North. Subsequent events have led men to forget that Millard Fillmore, then a representative from New York, was one of Mr. Adams's early co-laborers in the anti-slavery cause, and that in the important debate on the admission of Arkansas, with a constitution making slavery perpetual, Caleb Cushing of Massachusetts led the radical free sentiment of New England. A large number of distinguished Democrats in the North also entertained the strongest anti-slavery convictions, and were determined, at the risk of separating from their party associates, to resist the spread of slavery into free territory. Among the most conspicuous of these were Salmon P. Chase, John P. Hale, Hannibal Hamlin, Preston King, John M. Niles, David Wilmot, David K. Cartter, and John Wentworth. They had many co-laborers and a band of determined and courageous followers. They were especially strong in the State of New York, and, under the name of Barnburners, wrought changes which affected the political history of the entire country.