This office is not to be confounded with the officium parvum Beatae Mariae.

It was called, too, the Divine Office (officium divinum), because it has God for its principal object and is recited by persons consecrated to God.

It is called the ecclesiastical office (officium ecclesiasticum), because it was instituted by the Church.

Libri et alia necessaria ad officium praeparantur et legenda studiose ante praevisa, quando et quomodo sint dicenda dicuntur (Intit.