From the earliest times in the Catholic Church, the altar has been the focus of the liturgy; hierarchically, it is the highest point in a church building, representing Christ Himself, and so it is at the “head” of the church, laid out as the Mystical Body of Christ.One way of thinking about the church, theologically as well as architecturally,is to begin with the church’s raison d’être, the holy altar, and allow the building to grow out from there.”
The Church Building as a Sacred Place, Duncan G. Stroik