Answer:
Between 1820 and 1850, some Americans discriminated against Irish immigrants because they were Catholic.
Step-by-step explanation:
Many Protestant Irish emigrated to America during the industrial revolution in the 18th and 19th centuries. They were followed by millions of Catholic Irish during and after the Great Famine, that went from 1845 to 1852.
As has happened with many other immigrant communities, Irish Americans have long been subject to stereotypes that portrayed them as violent and disordered people, prone to alcoholism and criminal life as members of street gangs or criminal associations, illegal political voters and catholics who responded tho the Pope's will.