Immigration.

During the first half of the nineteenth century the Roman Catholic Church in the United States was transformed from a tiny religious minority
into the largest church in the nation. There had been many Catholics among the earliest European explorers and settlers of the North American continent, and the
colony of Maryland became a haven for English Catholics. But Catholicism was still the smallest denomination in the nation, with only 195,000 members. In the 1830s this situation began to change dramatically as tens of thousands of Catholic immigrants flooded into the United States from Ireland and Germany. These new
immigrants greatly altered the ethnic makeup of the American Catholic Church, which grew to 1,600,000 members by 1850, and changed the religious composition
of the United States as a whole.

Irish and Germans.

The first significant wave of Irish immigration to America was prompted largely by social and economic stresses caused...