In its official documents, the Church identifies the forms of the Roman Rite Mass by the editions of the Roman Missal used in celebrating them. Thus Pope Benedict XVI referred to this form of the Roman Rite Mass by linking it, in his motu proprio "Summorum Pontificum" of 7 July 2007, with "the Roman Missal promulgated by Pope Paul VI in 1970" or, in his accompanying letter of the same date to the bishops of the Church, "the Missal published by Paul VI and then republished in two subsequent editions by John Paul II".