The Native American Party, renamed in 1855 as American Party, and commonly named Know Nothing movement, was an American political party that operated on a national basis during the mid-1850s. It promised to purify American politics by limiting or ending the influence of Irish Catholics and other immigrants, thus reflecting nativism and anti-Catholic sentiment. It was empowered by popular fears that the country was being overwhelmed by German and Irish Catholic immigrants, whom they saw as hostile to republican values and controlled by the Pope in Rome. Mainly active from 1854 to 1856, it strove to curb immigration and naturalization, but met with little success. Membership was limited to Protestant men. There were few prominent leaders, and the largely middle-class membership fragmented over the issue of slavery.The most prominent leaders were U.S. Representative Nathaniel P. Banks, and former U.S. Representative Lewis C. Levin. The American Party nominated former President Millard Fillmore in 1856. He was never a member, nor a nativist.