Songfacts®:

• In 1864 Sabine Baring-Gould was appointed curate of the mission church at Horbury Bridge in Yorkshire. One of the big occasions was the Whit Monday procession - seven weeks after Easter - when the children marched to an adjoining village, headed by a cross and banners, to share in a united festival. They were accustomed to sing while marching, and the new curate sat up most of the night before the holiday writing them a special hymn for the procession.
  
  The following day, he taught the words of "Onward, Christian Soldiers" to the children," which he had set to a melody from the slow movement of Joseph Haydn's Symphony in D, No. 15.
• The hymn was printed in an English church periodical, the Church Times; but not much notice was taken of it till 1871 when Sir Arthur Sullivan (of Gilbert & Sullivan fame) wrote for it the celebrated tune we now sing. He penned the melody while staying with his friend Ernest Clay Ker Seymer, at his large house at Hanford, Dorset. Sullivan dashed it off in a few minutes in the drawing-room, naming the march "St. Gertrude" after Clay Ker Seymer's wife. "We sang it in the private chapel," Gertrude Clay Ker Seymer recalled, "Sir Arthur playing the harmonium."
• When President Franklin D. Roosevelt met with Sir Winston Churchill on August 14, 1941 to sign the Atlantic Charter, both leaders chose a hymn to be sung at a special service. Churchill selected, "Onward Christian Soldiers" and both American and British servicemen sang the song together.
• The hymn was sung during the funeral of President Dwight D. Eisenhower at the National Cathedral in the District of Columbia March 31, 1969.
• Among the numerous uses of the song in movies was during a scene in 1939's Stanley and Livingstone where Dr. Livingstone leads African natives in singing this hymn. It was also sung three years later at the end of the Oscar-winning movie Mrs. Miniver.