He favoured the Jesuits, especially in their conflict with the Jansenists, forbade in 1661 the translation of the Roman Missal into French, and in 1665 canonized Francis of Sales.
Agnus Dei is also the popular name for the anthem beginning with these words, which is said to have been introduced into the missal by Pope Sergius I.
The first book printed in Lausanne was the missal of the cathedral church (1493), while the Gazette de Lausanne (founded 1798) took that name in 1804.
In 1902, under Leo XIII., a commission under the presidency of Monsignor Louis Duchesne was appointed to consider the Breviary, the Missal, the Pontifical and the Ritual.
He is attended by a minister with a vase of holy water, an aspergillum and a copy of the Rituale or missal.