As part of Michael Doheny, Esq.'s 1857, essay "Memoir of the Father Geoffrey Keating, D. D.", included within John O’Mahony’s translation of Geoffrey Keating’s “The History of Ireland”, Doheny writes, "As early as the year 1179, only ten years after the landing of Fitzstephens, we find the name “Halis Keting” a subscribing witness to a grant to Dunbrody Abbey by Herve de Montmorencie."

This "Halis Keting" is often thought to be the first known reference to what is now the Keating surname. His (presumed) descendants, including myself, are often curious about the man and his times.

As an amateur genealogist/historian, I'd love to find a copy of this primary source. However, I only find references to the grant, never a pointer to the repository that contains or contained it. The Abbey's historical center itself is unaware of the grant. The National Archives of Ireland seem to be a possibility, but would this be more likely found in the archives of a museum? Is this document something that may have been available to Doheny and others, but has since been lost? Where does this and other documents of that time reside? Are they even accessible to amateurs?

I guess in many ways, this all comes down to a meta question - how do historians find the primary resources for their chosen interest? Are there published indexes to sources?