According to one of  Frank’s biographers, the lovely melody of Panis Angelicus first originated as an improvisation during the 1861 Christmas service. In 1872 he turned it into a motet for tenor, organ, harp, and double bass/cello, and published it in the same year (it is often performed by a soprano and with reduced instruments). The composer later added it to his Mass op. 12 of 1860.