Ineffabilis Deus - In this key papal bull (the title of which means "ineffable God" in Latin) Pope Pius IX defined ex cathedra the dogma of the Immaculate Conception of the Blessed Virgin Mary.
Munificentissimus Deus -This Apostolic constitution (the title of which means "most bountiful God" in Latin) was issued by Pope Pius XII on November 1, 1950.