I would agree with about not being sure that the sources given mention the subject I would go further and suggest the sources need examination and verification here As a priority I would suggest that someone with JSTOR access examine the reference used for asserting that Patrick was the son of John O Neill and a Madame de Buixin which is sourced to an article by Micheline Walsh The Will of John O Neill Third Earl of Tyrone the article would of course be a reliable source but we need to confirm that the details ascribed to this article are actually there The Walsh article is available here on JSTOR However there are other problems with the article particularly with chronology that I can see the article asserts that Patrick born in 1622 and per the article is the younger brother of Don Hugo Eugenio O Neill According to sources found for the article for Patrick s father in particular an article by Tom s Fiaich writing in his capacity as Professor of History at Maynooth rather than any clerical capacity Don Hugo Eugenio was not born until after O Neill seniors 1630 trip to Madrid While the article s assertion that he maintained a lengthy affair with a Countess of the O Donnell family is true in the sense that Hugo s mother was Isabel O Donnell and O Neill senior and Isabel O Donnell never married and they were together long enough to produce Hugo and a sister Catalina all this happened during the 1630s not the 1620s and in Madrid not in Brussels Another chronology problem raised by the O Fiaich article is that it raises the prospect of a political marriage in 1627 between O Neill senior and another O Donnell Mary Stuart O Donnell This marriage didn t happen but we still have a problem if O Neill was married to Madame de Buixin in 1620 or 1621 what happened to her that left him free to marry in 1627 and yet have to make provisions for Madame de Buixin in his will in the late 1630s