Number of Túatha? 
Does anybody have any knowledge of how many túatha 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 100 túatha in Ireland in the middle ages. And if, as this article says, a Túath had about 10,000 people that would mean about 1 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 100 figure, as I do distinctly remember being told that number in school?