number of t atha does anybody have any knowledge of how many t atha there were in ireland obviously it was constantly changing but does anyone know the average number through the period they existed i remember hearing from school that there was about t atha in ireland in the middle ages and if as this article says a t ath had about people that would mean about million on the whole island which sounds about right from what i've heard of population estimates of the time so should i just add in the figure as i do distinctly remember being told that number in school