From Ohio History Central
Roman Catholics are the largest single Christian body in the world. They consist of those Christians who follow the dictates of the bishop of Rome, the Pope. In 1990, more than 950 million people (approximately seventeen percent of the world's entire population) belonged to the Roman Catholic Church.
Roman Catholics base their teachings on God's word as printed in the Bible. Over time, Roman Catholics have accepted various church traditions, although not found in the Bible, as sanctioned by God. The same holds true for decisions of the Pope and the various Roman Catholic Church governing bodies. Roman Catholics believe that these traditions and decisions are correct interpretations of God's word and desires. Roman Catholics believe that a person must have faith in God and in Jesus Christ to attain salvation. Followers must atone for their sins while on Earth or face purgatory, a place that God sends souls to be cleansed of their sins before gaining entrance to heaven. Roman Catholics also believe that they can help the deceased gain entrance into heaven more quickly by praying for their souls.
Prior to 1054, Christianity really only consisted of a single branch: Roman Catholicism. A vast majority of Christians, although not all, followed the teachings of the Pope and his predecessors. In 1054, Catholicism split into the Eastern Orthodox Church and Roman Catholicism. No longer did all Catholics follow the dictates of the Pope. The Christian religions became more diverse in the 1500s, with the Protestant Reformation. Numerous people began to oppose Roman Catholic policies and teachings. The Protestant branch of Christianity originated, giving birth to numerous Christian denominations, including the Baptists, Lutherans, Methodists, Episcopalians, Mennonites, Amish, Quakers (Society of Friends), and Congregationalists, among many others.
Catholics were among the earliest Europeans to arrive in the New World in the late 1400s and the 1500s. Roman-Catholic monarchs governed both Spain and France, and they hoped missionaries would spread the gospel to the Native Americans. The first Roman Catholics to settle in British North America came to escape religious persecution in England. By the 1600s, Anglicanism, a Protestant faith, had become the official religion of England. Non-Anglicans faced religious persecution for not following the state religion.
Roman Catholics began to arrive in large numbers in Ohio during the early 1800s. Catholics erected their first church near Somerset in 1818. Many of Ohio's Catholics were German and Irish immigrants, who sought employment on the canals and railroads. Most Ohioans were Protestants and some strongly disliked the Roman Catholics. Many Protestants contended that the Catholics were more loyal to the Pope than to the United States, and thus, the Catholics could not be trusted. Many Ohioans also denounced the Catholics for their opposition to public education. Many Roman Catholics preferred to educate their children in private schools rather than sending their children to secular institutions. The Catholics argued that they should not have to pay taxes to support public schools if they did not utilize them. The Catholics became a favorite target of the Know-Nothing Party during the late 1840s and 1850s. As additional Catholic immigrants arrived in Ohio during the mid and late 1800s, Catholic influence continued to grow. By 1870, Cleveland had one of the largest Catholic populations in the United States. In Cincinnati, roughly seventy percent of all city residents belonged to the Roman Catholic faith in 1910. Although Protestants began to become more accepting of Catholics during the early 1900s, Catholics still faced some persecution. Many Catholics lived in their own communities, believing that they could attain safety in numbers.