The Know Nothing was a movement by the nativist American political faction of the 1840s and 1850s. It was empowered by popular fears that the country was being overwhelmed by German

German American

German Americans are citizens of the United States of German ancestry and comprise about 51 million people, or 17% of the U.S. population, the country's largest self-reported ancestral group...

 and Irish Catholic

Irish Catholic

Irish Catholic is a term used to describe people who are both Roman Catholic and Irish .Note: the term is not used to describe a variant of Catholicism. More particularly, it is not a separate creed or sect in the sense that "Anglo-Catholic", "Old Catholic", "Eastern Orthodox Catholic" might be...

 immigrants, who were often regarded as hostile to Anglo-Saxon

White Anglo-Saxon Protestant

White Anglo-Saxon Protestant or WASP is an informal term, often derogatory or disparaging, for a closed group of high-status Americans mostly of British Protestant ancestry. The group supposedly wields disproportionate financial and social power. When it appears in writing, it is usually used to...

 Protestant values and controlled by the Pope

Pope

The Pope is the Bishop of Rome, a position that makes him the leader of the worldwide Catholic Church . In the Catholic Church, the Pope is regarded as the successor of Saint Peter, the Apostle...

 in Rome. Mainly active from 1854 to 1856, it strove to curb immigration

Immigration

Immigration is the act of foreigners passing or coming into a country for the purpose of permanent residence...

 and naturalization

Naturalization

Naturalization is the acquisition of citizenship and nationality by somebody who was not a citizen of that country at the time of birth....

, though its efforts met with little success.