The Order of the Star Spangled Banner (OSSB) was an oath-bound secret society in New York City. It was created in 1849 by Charles Allen to protest the rise of Irish, Catholic, and German immigration into the United States.

In order to join the Order, a man had to be at least twenty-one years old, a Protestant, and willing to obey the Order's dictates without question. Members were Nativists, citizens opposed to immigration. Members invariably responded to questions about the OSSB by claiming that they "knew nothing." This practice caused newspaper editor Horace Greeley to label them "Know Nothings." The OSSB would eventually form the nucleus of the nativist American Party.

From page 306 of The American Pageant textbook:

Older-stock Americans were alarmed by these mounting figures. They professed to believe that in due time the "alien riffraff" would "establish" the Catholic church at the expense of Protestantism and would introduce "popish idols." The noisier American "nativists" rallied for political action. In 1849 they formed the Order of the Star-Spangled Banner, which soon developed into the formidable American, or "Know-Nothing," party - a name derived from its secretiveness. "Nativists" agitated for rigid restrictions on immigration and naturalization and for laws authorizing the deportation of alien paupers. They also promoted a lurid literature of exposure, much of it pure fiction. The authors, sometimes posing as escaped nuns, described the shocking sins they imagined the cloisters concealed, including the secret burial of babies. One of these sensational books ? Maria Monk's Awful Disclosures(1836) ? sold over 300,000 copies.