...Irish dance music was performed at a ceiili...
and I'll raise you one i , ceiiili :)
I'm afraid I take Wiki very lightly as a serious resource, maybe it would be more acceptable to think that Irish music and dance evolved side by side, one discipline feeding off the other. Many times at Irish sessions I've been at, the musician/s have struck up a tune and people have just started an impromptu dance or set and in doing so have had no qualms about telling the musician/s to speed up or slow down to their needs, but I've never heard a dancer say "you're playing the wrong tune".
I'm not sure where this thread is leading as the speed at which tunes are meant to be played varies from tune to tune and area to area and different dancers will want to dance at different tempi. To my mind, I like to hear a tune played well, no matter how fast or slow it is played. Is it just a matter of personal choice?