Taken from John Francis Gilbert’s A Contemporary History of Ireland, from 1641 to 1652, published 1879. The letter has been translated from its original Latin.

Very respected Father,

After various attempts that were partly in vain and partly unsuccessful, in which there seemed to be hope of helping our afflicted country, and after a greater delay than I would have wished in these investigations, I have now resolved not to stay any longer in this matter, nor to withdraw my efforts from my own person to assist my country. Therefore, I have decided to expose myself to the dangers of land and sea, so that I may not appear to be absent from my country through my own presence. I am now preparing to set sail with some nobles of my people. I bid farewell to Your Paternity and express my deep gratitude for your zeal for the country and your affection towards me. I did not think it necessary to request Your Reverence to continue urging the affairs of the country with His Holiness, as your zeal towards it is well known and attested by numerous letters from England, France, Holland, and even Ireland, which all declare that everything is succeeding happily for Catholics every day, and if not for the scarcity of gunpowder and military equipment, they would already have the whole kingdom under their power. Oh, if His Holiness knew how tormenting and destructive this heresy is believed to be to its supporters, there would be no doubt that he would take measures to remedy it. But we leave this to Your Paternity’s zeal and prudence, and with all devotion, we humbly recommend ourselves and our afflicted country to the sacrifices and prayers of you and your subjects.

Brussels, this 7th day of June 1642.
Your Paternity’s humble and devoted servant, ready for all obedience,
Don Eugenio O’Neill.

As one of the first things to be recommended, I ask Your Paternity to kindly present these attached letters to His Holiness, in which I humbly ask for blessings for myself and others who fight for the faith.