The same year the Athenaeum moved to Beacon Hill, the demographics of the city began to change dramatically. Between 1847 and 1853, Irish migration to the United States peaked in the wake of the potatoe famine and Boston was one of the main ports of entry. By 1850 about 20 percent of Boston's population was Irish. Anti-Irish and anti-Catholic sentiment quickly gained traction such that the anti-immigrant Know Nothing Party (in Massachusetts known as the American Party) swept state elections in 1854, installing a Know-Nothing governor, Henry J. Gardner.