"An extraordinary form of the Roman Rite" is the term used in Pope Benedict XVI's motu proprio Summorum Pontificum for the liturgy of the 1962 Roman Missal, widely referred to as the "Tridentine Mass". The phrase indicates that the liturgy of the 1962 Missal, the celebration of which was permitted more widely by the motu proprio, differs from the normal present-day liturgy of the Roman Rite (the "ordinary form"). At present, the ordinary form of celebration of Mass of the Roman Rite is that established in the revision of the Roman Missal, promulgated by Pope Paul VI in 1969.