What sudden blaze of song. J. Keble. [Christmas.] Published in his Christian Year, 1827, in 11 stanzas of 6 lines, as the poem for Christmas Day. In the American Church Pastorals, Boston, 1864, stanzas i., v., ix. are given in an altered form, but beginning with the same first line.
--John Julian, Dictionary of Hymnology (1907)