According to the oral history of my family, Patrick and his brother Luke who married Mary Delamer, a sister of Brigid, in 1859, (also in Newtowncashel) were born in the townland of Clooncraff, Co. Roscommon.
After an intensive month on rootsireland.ie, to my delight and amazement, I have found the following;
The children of John Brennan & Mary Fox;
Honor baptised 1823 Roman Catholic Parish of Roscommon (and Kilteevan)
Patrick 1826, as above
John 1827, as above
Luke 1830, as above
Michael 1834, as above
Catherine 1837, as above
This implies a potential date of birth of late 1700's or 1800 for John Brennan & Mary Fox and a potential marriage date of 1822
The dates and names match the oral history of my family. This is not proof of course. There is a mighty amount of work yet to be done. But early stage research into marriage and land records do not contradict the possibility that I am on the right track. It may be that existing paper records will not give me the confirmation I need. It may be that my Patrick and Luke Brennan's records simply do not survive and this is another family entirely. As with many Irish families it may be that only DNA tests will establish a clear link but at least now I have a possible lead that I can pursue.
If you think that you are connected to this family, the children of John Brennan & Mary Fox please leave your name and email address in the comments box below and and maybe together we can puzzle it out!