Most of us understand that a hymn is a religious song with a text arranged in verses. The verses are arranged in stanzas of similar meter. The terms stanza and meter might prove difficult to precisely define. But most people could probably recognize a hymn when they hear one being sung.

In a literary or poetic sense, a hymn consists of only the lyrics. Hymnals (books containing a collection of hymns) list titles for both hymns and hymn tunes. In addition, separate indexes list names of authors and composers.

A tune paired with a particular hymn may have been composed specifically for that hymn either contemporaneously or later, or it may have been paired according to the judgement of the editor of the hymnal.

Publishers may publish together any hymn with any hymn tune in the same meter. With an effective pairing of a hymn and a hymn tune, the music usually comes to be popularly identified with the title of the poetic hymn text instead of by its actual tune name.

Anglican pastor Augustus Toplady (1740-1788) wrote "Rock of Ages." Years later, Thomas Hastings, an American composer and music teacher, composed a tune to be sung with this hymn. Hastings named it "Toplady" to honor the author and to strengthen the association of his tune with the hymn.

This pairing of hymn and tune is one of the most popular and easily recognized hymns in the United States. It is sung in homes and churches and featured in movies and recorded by popular singers.

In the United Kingdom, hymn editors usually pair “Rock of Ages” with the tune “Redhead 76.” 19th-century English composer and church musician Richard Redhead composed this tune, which was a favorite of Prince Albert.