"O Valiant Hearts" is a hymn remembering the fallen of the First World War.
Words were taken from a poem by Sir John Stanhope Arkwright (1872–1954), published in The Supreme Sacrifice, and other Poems in Time of War (1919). It was set to music by the Rev. Dr. Charles Harris, Vicar of Colwall, Herefordshire 1909-1929.
The poem was later included as a hymn in both editions of the hymn book Songs of Praise. For the first edition, published in 1925, the music was set to a traditional tune, 'Valour', arranged by Vaughan Williams. In the second, larger edition of Songs of Praise, published in 1931, Gustav Holst composed the tune 'Valiant Hearts' especially for the hymn. In Songs of Praise Discussed, Valiant Hearts is described as 'a good bold tune, in triple time, with a suggestion of bell-chimes in the repeated first phrase, an effect which is enhanced by the nature of the accompaniment to the alternative unison version'. The alternative unison version referred to is written for verses 3 and 7. However, it is to the Harris tune that the hymn is now almost always sung. A very early recording (to Harris's beloved tune) by the boy soprano Harold Langston was played at the Aldershot Tattoo in 1930 to vast crowds. The Episcopal Church (USA)'s 1940 Hymnal has it to Valiant Hearts and to Birmingham.