Canonicity

This page groups hymns by whether they come from scripture itself or were composed later. Wikipedia notes that "non-scriptural hymns (i.e. not psalms or canticles) from the Early Church still sung today include 'Phos Hilaron', 'Sub tuum praesidium', and 'Te Deum'." Browsing by canonicity lets a visitor separate a scriptural psalm set to music from a hymn composed outside the biblical text.