Office of the Dead

The Officium Defunctorum, or Office of the Dead, is a part of the Divine Office whose purpose is to allow the living, with one voice, to aid the faithful departed through prayer and supplication. It is a liturgy proper, which is to say that it is fully structured and regulated by rubrics, and is so ancient that its origins predate Christianity. 

Unlike the rest of the Divine Office, which involves rotation through a psalter, or psalm cycle, the Officium Defunctorum is, in the spirit of simplicity and mourning, fixed in its entirety with no variation by day nor season. It is a highly ancient and venerable form of prayer, and one which is so precious that it has been codified by the Church for well over a millenium.

"The Liturgy of the Hours, though always ancient, is ever new—a true school of prayer for the People of God." - Pope Saint John Paul II, Apostolic Letter: Novo millennio ineunte, issued on January 6, 2001