Passus Duriusculus

The passus duriusculus, or chromatic fourth, is a musical figure consisting of a chromatic descent, usually spanning a fourth, and is traditionally associated with grief and lamentation. Perhaps the most emblematic example is Purcell’s lament bass, which repeats itself on and on beneath the aria “When I am Laid,” sung by a suicidal character in his opera Dido and Aeneas. It is common to find it in sombre passages, as I mentioned, often carrying dark and grieving associations.