Major revivals broke out in the Civil War armies. In the Union Army, between 100,000 and 200,000 soldiers were converted; among Confederate forces, approximately 150,000 troops converted to Christ. Perhaps 10 percent of all Civil War soldiers experienced conversions during the conflict.
A "Great Revival" occurred among Robert E. Lee's forces in the fall of 1863 and winter of 1864. Some 7,000 soldiers were converted. Revivals also swept the Union Army at that time. Sometimes preaching and praying continued 24 hours a day, and chapels couldn't hold the soldiers who wanted to get inside.