The Refugees Who Became a Fire

In 1722, a ragged band of Protestant refugees stumbled onto the estate of Count Nikolaus von Zinzendorf in Saxony, Germany. They were Moravians, Lutherans, Calvinists, Schwenkfelders — believers fractured by theology and scarred by persecution. They settled a plot of land called Herrnhut, meaning "the Lord's watch," and promptly began arguing with one another. For five years, the community splintered over doctrine and practice.…