The stable, prosperous, and relatively homogeneous city underwent a major shock in the 1840s, with the massive influx of Irish immigrants. The peasantry in Ireland had faced increasing difficulty for several decades, but the potato rot, which first appeared in that country in 1845 created a disaster. Hundreds of thousands immigrated, many to Boston. Several of the major shipping companies seized the opportunity to carry Irish peasants in steerage at low costs. By 1855 the Irish-born made up 46,237 of Boston's 160,400 residents (Kennedy, 1992).
The city was ill prepared to deal with the newcomers. ...