The U.S. Pledge of Allegiance is a patriotic recited verse that promises allegiance to the flag of the United States and the republic of the United States. The first version was written in 1885 by Captain George Thatcher Balch, a Union army officer in the Civil War who later wrote a book on how to teach patriotism to children in public schools. In 1892, Francis Bellamy revised Balch's verse as part of a magazine promotion surrounding the World's Columbian Exposition, which celebrated the 400th anniversary of Christopher Columbus' arrival in the Americas.