The contribution analyses the descriptive definition of liturgy as a performance of Christ's priesthood as it is presented in Chapter 7 of the Constitution of Sacred Liturgy. The analysis is based on careful studies of the council documents which allows to follow the development of the text during the council.
The access to authentic sources shows both the continuity of preceeding documents of magisterium and the new elements which are the fruit of theological work and which the council integrated into its teaching.