it's "old" but i believe robert bartlett wrote on that subject in his book Gerald of Wales.

At 08:31 PM 2/5/01 +0000, you wrote:

Hello,

I'm preparing a paper in respect of Cambrensis' "History and Topography
of Ireland", in particular his political and religious agenda in respect
of the Irish, their religion of antiquity and Christianity. I wondered
if anyone was aware of any titles or papers which may broach upon this
issue and any current thoughts in respect of this title.
Thank you in anticipation.

Michael.