The bloodstained Order of United Americans first appeared in New York City in 1844 and soon spread to Massachusetts, Pennsylvania, New Jersey, and Connecticut. Catholic churches had been torched now and then since the mid-1830s (actually black churches too, but not on account of religion). In 1834 a nativist mob had burned the Convent of the Ursuline nuns in Charlestown, Massachusetts. Now arson became endemic, climaxing in Philadelphia in 1844, when a mob of six hundred self-proclaimed American Republicans burned down St. Micheal’s and St. Augustine’s Catholic churches and torched many Irish residences. The rioting lasted three days, killing thirteen and wounding fifty. In Pittsburgh in 1850 a candidate running on the “People’s and Anti-Catholic” ticket won the mayoral race. During the 1850s Massachusetts and Connecticut enacted voter literacy tests in an attempt to curtail immigrant Democratic voting power. By the mid-1850s clubs of the Order of United Americans flourished in sixteen states.
Much early anti-Catholic violence was more or less spontaneous and poorly organized, driven by fear that the Irish would lower wages or increase crime. But nativism gained an important institutional basis with the founding in New York City, in about 1850, of the secret Supreme Order of the Star-Spangled Banner. Members soon became labeled “know-nothings” because they customarily responded to queries about their order with “I know nothing”. Members had to be born men in the United States of native-born parents. Natives married to Catholics could not join. Know-Nothings had a broad agenda that differed according to their class and region.They especially hated Catholics, but they also opposed liquor and political corruption. In New England, they challenged the mass voting of immigrants for the proslavery Democratic Party.
In terms of their tactics, Know-Nothing clubs like the Order of United Americans and the Supreme Order of the Star-Spangled Banner traded on patriotism. Most local chapters took the names of founding fathers or heroes and battles of the American Revolution. A political party spun out of the Supreme Order of the Star-Spangled Banner was actually named the American Party. So patriotic a title encouraged members to brand opponents “anti-American”. In the Midwest, for instance, where Germans had settled and voted in large numbers, refugees from the European revolutions of 1848 almost automatically seemed anti-American on account of their suspected radicalism.