The Protestant group known as Moravians originated in the 15th century in Bohemia and Moravia (both in present-day Czech Republic) as the Unitas Fratrum, which means "Unity of Brethren." Members of the Unitas Fratrum followed the teachings of the Bohemian reformer, Jan Hus. They took the name "Moravians" in the early 18th century as a reference to the group's place of origin. Moravians were among the many religious groups that migrated to colonial America in search of social and economic opportunity and the chance to spread their religious beliefs.

In 1741, the Moravians settled along the Lehigh River in Pennsylvania, a colony known for its rich natural resources and its extraordinary toleration of religious ideas. Pennsylvania became host to a heterogeneous population of many ethnic groups who spoke different languages and had different social and religious practices. By the 1750s, several hundred Moravians lived in Bethlehem. In an effort to Christianize American Indians and Africans in North America, they eventually established 32 mission towns. Bethlehem, however, remained the seat of the Moravian community as well as the industrial center.