Some scholars have suggested that Wade fashioned ADESTE FIDELES from melodic fragments of stage music. In the original Wade manuscripts the tune was in triple meter. It was changed to its present form by 1782 and published in the elder Samuel Webbe's (PHH 112) Essay on the Church Plain Chant.

Some Protestant hymnals have published ADESTE FIDELES as a setting for other texts; for example, Ira D. Sankey (PHH 73) used this tune for "How Firm a Foundation." But the tune and text are now commonly used together, and "O Come, All Ye Faithful" remains one of the most-loved Christmas hymns.

The tune is a fuguing tune; it begins chordally and uses some imitation in the refrain. The harmonization in the Psalter Hymnal is from The English Hymnal (1906); the descant is from Hymns Ancient and Modern (revised ed., 1947). Sing the stanzas in unison and the refrain in parts.

--Psalter Hymnal Handbook