What is the english name of the encyclical which was written by the Bishop of Rome and the sovereign of Vatican City?
Pope Francis Pope Francis (Latin: "Franciscus" ; Italian: "Francesco" ; Spanish: "Francisco" ; born Jorge Mario Bergoglio; 17 December 1936) is the 266th and current Pope of the Catholic Church, a title he holds "ex officio" as Bishop of Rome, and sovereign of Vatican City. He chose Francis as his papal name in honor of Saint Francis of Assisi. Francis is the first Jesuit pope, the first from the Americas, the first from the Southern Hemisphere, the first to choose a name not used by a predecessor since Lando in 913 AD, and the first pope from outside Europe since the Syrian Gregory III, who reigned in the 8th century.
Ad diem illum Ad diem illum laetissimum is an encyclical of Pope Pius X, on the Immaculate Conception dated February 2, 1904, in the first year of his Pontificate. It is issued in commemoration of the fiftieth anniversary of the dogma of the Immaculate conception. The first reason for Pius to write the encyclical was his desire to restore of all things in Christ, which he had defined as his motto in his first encyclical letter. It explains the Mariology of Pius X.