As the occasion requires

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

A hymn is a song of praise, prayer or devotion composed for use in communal worship, distinct from scripture in that it is written by a known or anonymous author specifically to be sung rather than received as revealed text, and distinct from an ordinary devotional song in that a tradition has typically adopted it into regular, repeated liturgical use rather than treating it as one performer's individual composition.

An entry records a hymn's text and its role within its tradition's worship, when and how it is typically sung, on what occasions, and by whom, congregation, choir or a designated singer, since a hymn's place in a service is often as fixed by convention as its words are. Where a hymn carries a well documented tune tradition, the entry notes that too, since the same words are frequently set to more than one melody across different communities.

Hymnody varies enormously across traditions in both form and function, from the metrical psalms sung congregationally in Reformed Protestant worship to the chanted hymns of Eastern Orthodox liturgy to devotional bhajans sung in Hindu worship, and an entry describes a hymn within its own tradition's conventions rather than measuring it against any single tradition's idea of what a hymn should sound like or how it should be used.

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Writing a hymn is rarely a solitary literary act in the way writing a poem for private reading is; a hymn is composed to be sung by a specific community under specific musical conventions, which shapes its meter, its repetition and its structure well before any question of its content arises. Byzantine hymnography, one of the oldest continuously practiced hymn traditions, developed an elaborate system of eight modes, and a hymn's text was typically composed to fit an existing melodic pattern rather than the melody being written afterward to suit the words.

That close bond between text and melody makes a hymn's transmission a musical problem as much as a literary one. Byzantine chant was passed down for centuries through a specialized notation system, and through direct oral instruction from a trained cantor to a student, well before that notation could reliably capture every nuance of pitch and ornamentation, so a hymn's sung tradition often carries information a bare printed text of its words cannot.

Comparing how differently traditions have handled this same problem, some relying on precise notation, others on oral transmission through a chain of trained singers, is itself a way of seeing how central the sung, communal performance of a hymn is to what a hymn actually is, as opposed to a poem that merely happens to have been set to music after the fact.