(The Conversation) — On Flag Day, a historian of religions in America explains how the Pledge of Allegiance, which honors the American flag, is part of American civil religion.

Francis J. Bellamy wrote the Pledge of Allegiance in 1892 and found a powerful ally in the patriotic National Education Association, which brought it to the American schoolroom. Here's his story.

Many remember starting schooldays with the Pledge of Allegiance. Some stand and salute the American flag when attending a parade — maybe for the Fourth of July.

In fact, many schools and public buildings didn’t even have national flags, according to “To The Flag,” a 2005 book on the history of the Pledge, by Richard J. Ellis.