The following is taken from a Jan. 24, 2010 press release by the Paulus Institute in Washington DC, which is sponsoring the Mass, commenmorating the fifth anniversary of the pontificate of Pope Benedict XVI.
The mass is to be celebrated by the Vatican’s Cardinal Castrillón Hoyos, who reportedly has stepped aside following reports he wrote a letter in 2001 praising a French bishop for refusing to hand over to the police a priest who had raped children. Organizers are now reportedly searching for a replacement prelate, one immersed adequately in the Latin language and ceremony.
The mass, set for Saturday, has been marketed as "the First Traditional Mass at the National Shrine’s High Altar in 45 Years." It is to be "commemorated in the Great Upper Church of the Basilica of the National Shrine of the Immaculate Conception, Washington DC, by a Pontifical Solemn High Mass in the 'Extraordinary form'—commonly known as the 'Traditional Latin Mass' or 'Tridentine Mass'— celebrated by the Vatican prelate Dar'o Cardinal Castrillón Hoyos of Colombia."
By way of background, according to the Paulus Institute: In July of 2007 Pope Benedict issued the apostolic (papal) Summorum Pontificium (of the Supreme Pontiff), in which he confirmed the permissibility this Mass. It is one of the two uses of the same rite of the Eucharistic Liturgy, along with the Missal of Pope Paul VI in 1970 (the “Ordinary” form). Evolving since the early days of the Christian Church, the Mass was essentially in place by the 6th century during the papacy of Pope St. Gregory the Great and codified by Pope St. Pius V in the 16th Century. It was last changed by Pope John XXIII in 1962 and so used during the Second Vatican Council. In 1984 Pope John Paul II permitted use of the Missal of John XXIII, and further facilitated it in 1988 and 1992. Pope Benedict noted that the Latin liturgy of the Church in each century of the Christian era “has been a spur to the spiritual life of many saints and reinforced many peoples in the virtue of religion and [facilitated] their piety,” adding, “What earlier generations held as sacred remains sacred for us too.” Writing that since this Mass “must be given due honor for its venerable and ancient usage ... let us generously open our hearts and make room for everything that the faith allows.” The pope noted in an accompanying letter that “young persons too have discovered this liturgical form, felt its attraction, and found in it a form of encounter with the Mystery of the Most Holy Sacrifice particularly suited to them.”