This tune [EVAN], "the popularity of which in Scotland, America, and the Colonies is quite unprecedented" (Tonic Sol Fa Reporter, May 15, 1870), consists of the 1st, 2nd, 7th, and 8th strains of "O Thou dread Power" a sacred song by the Rev. W.H. Havergal, the melody being unaltered. EVAN II is the entire melody of the same song, harmonized by the author as a C.M.D. about the year 1867. The following note, written upon a copy of EVAN, given as autograph at the request of a friend, supplies his own account of its origin:
"EVAN, framed by Dr. Lowell Mason of New York, from a sacred song, 'O thou dread Power,' by W.H. Havergal, M.A., original air first published in 1847. The beautiful words of the sacred song were written by Burns for the family of Dr. Lawrie. The music to them is in triple time, and in the key of A-flat. The tune EVAN comprises only part of the original melody. As the American arrangement was a sad estrangement, I have reconstructed the tune after a more correct form. Why it was called EVAN I know not. Still I do not approve the tune. Leamington, March 19th, 1870. W.H. Havergal."
—Havergal’s Psalmody and Century of Chants (London: R. Cocks, 1871), p. xix.