The
Know Nothing movement was an American political movement 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.