67 It is scarcely necessary to say here how painful it is to Us to note that from this galaxy of friendly powers which surround Us one is missing, Italy, Our own dear native land, the country where the hand of God, who guides the course of history, has set down the Chair of His Vicar on earth, in this city of Rome which, from being the capital of the wonderful Roman Empire, was made by Him the capital of the whole world, because He made it the seat of a sovereignty which, since it extends beyond the confines of nations and states, embraces within itself all the peoples of the whole world. The very origin and divine nature of this sovereignty demands, the inviolable rights of conscience of millions of the faithful of the whole world demand that this sacred sovereignty must not be, neither must it ever appear to be, subject to any human authority or law whatsoever, even though that law be one which proclaims certain guaranties for the liberty of the Roman Pontiff.
Source: Ubi Arcano Dei Consilio (Vatican.va)