In 1966, Pope Paul VI issued norms to apply these instructions through the motu proprio Ecclesiae Sanctae.
He was embrolied in scandal after Pope Benedict XVI on 7 July 2007 issued the motu proprio Summorum Pontificum liberalising the use of the Latin Mass.
In 1891, however, Pope Leo XIII issued a Motu Proprio re-founding the Specola Vaticana (Vatican Observatory) and a new observatory was built on the walls at the edge of the Vatican.
Pope Clement XIII, on learning of this wish of Maria Theresa, granted this title motu proprio to the queen and her successors, by virtue of the Papal Brief "Carissima in Christo filia", of 19 August 1758.
Bonum sane was a motu proprio on Saint-Joseph written by Pope Benedict XV and delivered on July 25, 1920.
The book argues for a return to the Tridentine Rite of the Mass, the form of the Roman Rite before the Second Vatican Council, the use of which, in accordance with the Roman Missal of 1962, is authorized, under certain conditions, by the 2007 motu proprio Summorum Pontificum.
But, since Pope Benedict XVI's motu proprio, Summorum Pontificum, use of the Tridentine rite has increased; this, along with other papal comments on the use of appropriate liturgical music, is promoting a new plainsong revival.