In Mediator Dei Pius XII is the first to explain in a magisterial document, vibrant with apostolic ardour, the basic prerogatives which entitle the liturgy to a post of the first order in the spiritual life. With Sacrosanctum Concilium the liturgical movement was seen to have "reached its maturity." Yet as Nichols asserts, Sacrosanctum Concilium "carried within it, encased in the innocuous language of pastoral welfare, some seeds of its own destruction." These texts are a tutorial in liturgical spirituality and tradition. Their comparison informs assessment of the liturgical practice of the Church today, and considerations for future reform.