9 But how does it happen that you, although not numerous, achieve such good deeds? Where did the people of Portugal get that vigorous strength with which they were able to dominate the shores of Africa and Asia and even the distant land of America? Without a doubt this came about because that nation, as the greatest poet of Portugal sang, persevered in an ardent and strong faith; also, your leaders were preeminent in Christian wisdom and prudence. Therefore, God used your nation as a precious instrument for admirable accomplishments.
Source: Saeculo Exeunte Octavo (Vatican.va)