Anti-Catholicism

Laws were passed against Roman Catholics when there were fewer than 50,000 members of the Catholic Church in the entire country.  New York had such a law on its books until 1806; Massachusetts until 1833.

Catholicism and the Pope were portrayed by "nativists" (people who feared foreign influences) as having a secret agenda to undermine the Protestant religion and the American way of life.   There were rumors of Vatican plots to poison Protestant leaders.  Awful Disclosures of the Hotel Drew in Montreal, written in 1836 by an alleged runaway nun, Maria Monk, confirmed her readers' suspicions of lechery behind convent walls. 

In August 1831, the Ursuline Convent in Charlestown , Massachusetts was deliberately burned down.  In 1844, Protestant mobs attached Irish homes in Philadelphia and dynamited their churches.  A few years later, they burned the Irish neighborhood of Lawrence , Massachusetts . 

In the 1850s, this anti-Catholic sentiment found a home in the Know-Nothing Party.