"The term "prehistoric" ceases to be valid some thousands of years B.C. in the near east but remains a warranted description down to about 500 A.D. in Ireland", Review by "A. T. L." of Prehistoric Art by T. G. E. Powell, The Journal of the Royal Society of Antiquaries of Ireland, Vol. 97, No. 1 (1967), p. 95, Royal Society of Antiquaries of Ireland, JSTOR