Hard to decipher, but others did it already:
"The Early Cross-Slabs and Pillar Stones at Church Island, near Waterville, C. Kerry" by Henry S. Crawford, The Journal of the Royal Society of Antiquaries of Ireland, Sixth Series, Vol. 16, No. 1 (Jun. 30, 1926), pp. 43-47 (
https://www.jstor.org/stable/25513388?s ... b_contents)
Quote:
No. 1 stands north of the church and close to it. Its dimensions are 5 feet 1 inch in height, 2 feet 1 inch in breadth and 4½ inches in thickness. On the west side is incised a ringed cross of four lines, with the Greek letters α and ω, ιης² and χρς occupying the intersections of the arms and ring. On the shaft of the cross, and beside it, is the inscription : bennocht Fanmain Anmchado - a blessing on the soul of Anmchadh.*
[...]
² The Greek ιης for Jesus seems, even at that date, to have been confused with the Latin I.H.S., as the Latin h is given instead of the Greek η, if capitals had been used these letters would have had the same form.
* A close examination of the photograph in Jrnl., xxxviii, appears to show a rounded a at the end of Anmchada and in bennacht where o was read in Mr. Lynch's paper. As Anmchado would be an old Irish genitive, the correct reading is important for dating the inscription
-Ep.
... so we get
bennacht Fanmain Anmchadain Modern Irish:
beannacht ar anam AnamchadhaAn(a)mchadh is a name, probably this monk:
https://en.wikipedia.org/wiki/AnmchadThe
F has an overline (= "for" = ar)
(see
http://www.gaelchlo.com/stair/neilson.pdf, Plate III)
(And there’s an overline over ιης and χρς.)