Jean Langlais' Suite médiévale and Vatican II
Jean Langlais (1907–1991) composed his organ Mass Suite médiévale in 1947, drawing on a rich tradition of French organ suites composed for use during the “low” Mass. Changes to the liturgy after the Second Vatican Council (“Vatican II”) in 1962 drastically reduced the role of the organ during the Mass, thereby eliminating the need for the French organ Mass. Suite médiévale is one example of a body of small-scale liturgical organ compositions that no longer carry their intended relevance due to changes to the liturgy.
Source: thediapason.com