This is Pope Leo XIII:
"We traverse in spirit and thought the wide expanse of ocean; and although We have at other times addressed you in writing - chiefly when We directed Encyclical Letters to the bishops of the Catholic world-yet have We now resolved to speak to you separately, trusting that We shall be, God willing, of some assistance to the Catholic cause amongst you. To this We apply Ourselves with the utmost zeal and care; because We highly esteem and love exceedingly the young and vigorous American nation, in which We plainly discern latent forces for the advancement alike of civilization and of Christianity.
2. Not long ago, when your whole nation, as was fitting, celebrated, with grateful recollection and every manifestation of joy, the completion of the fourth century since the discovery of America, We, too, commemorated together with you that most auspicious event, sharing in your rejoicings with equal good-will. Nor were We on that occasion content with offering prayers at a distance for your welfare and greatness. It was Our wish to be in some manner present with you in your festivities. Hence We cheerfully sent one who should represent Our person. Not without good reason did We take part in your celebration. For when America was, as yet, but a new-born babe, uttering in its cradle its first feeble cries, the Church took it to her bosom and motherly embrace. Columbus, as We have elsewhere expressly shown, sought, as the primary fruit of his voyages and labors, to open a pathway for the Christian faith into new lands and new seas. Keeping this thought constantly in view, his first solicitude, wherever he disembarked, was to plant upon the shore the sacred emblem of the cross. Wherefore, like as the Ark of Noe, surmounting the overflowing waters, bore the seed of Israel together with the remnants of the human race, even thus did the barks launched by Columbus upon the ocean carry into regions beyond the seas as well the germs of mighty States as the principles of the Catholic religion.
3. This is not the place to give a detailed account of what thereupon ensued. Very rapidly did the light of the Gospel shine upon the savage tribes discovered by the Ligurian. For it is sufficiently well known how many of the children of Francis, as well as of Dominic and of Loyola, were accustomed during the two following centuries to voyage thither for this purpose; how they cared for the colonies brought over from Europe; but primarily and chiefly how they converted the natives from superstition to Christianity, sealing their labors in many instances with the testimony of their blood. The names newly given to so many of your towns and rivers and mountains and lakes teach and clearly witness how deeply your beginnings were marked with the footprints of the Catholic Church.
4. Nor, perchance did the fact which We now recall take place without some design of divine Providence. Precisely at the epoch when the American colonies, having, with Catholic aid, achieved liberty and independence, coalesced into a constitutional Republic the ecclesiastical hierarchy was happily established amongst you; and at the very time when the popular suffrage placed the great Washington at the helm of the Republic, the first bishop was set by apostolic authority over the American Church. The well-known friendship and familiar intercourse which subsisted between these two men seems to be an evidence that the United States ought to be conjoined in concord and amity with the Catholic Church. And not without cause; for without morality the State cannot endure-a truth which that illustrious citizen of yours, whom We have just mentioned, with a keenness of insight worthy of his genius and statesmanship perceived and proclaimed. But the best and strongest support of morality is religion. She, by her very nature, guards and defends all the principles on which duties are founded, and setting before us the motives most powerful to influence us, commands us to live virtuously and forbids us to transgress. Now what is the Church other than a legitimate society, founded by the will and ordinance of Jesus Christ for the preservation of morality and the defence of religion? For this reason have We repeatedly endeavored, from the summit of the pontifical dignity, to inculcate that the Church, whilst directly and immediately aiming at the salvation of souls and the beatitude which is to be attained in heaven, is yet, even in the order of temporal things, the fountain of blessings so numerous and great that they could not have been greater or more numerous had the original purpose of her institution been the pursuit of happiness during the life which is spent on earth." http://www.vatican.va/content/leo-xiii/en/encyclicals/docuмents/hf_l-xiii_enc_06011895_longinqua.html