Hi Les,
The tradition from which the Clancy Bros drew their vast repertoire was the product of a vibrant oral (rural and urban) inheritance which drew from local traditional songs, stories and poetry in both the English and Irish language. Every locality had at least one bard-poet/song-maker who praised, satirised and pilloried. . There are many (Con Fada O'Driscoll from Cork comes to mind) who continue this tradition today.
The professional travelling musicians who would have played at fairs, hurling matches and other such social occassions, would also have been songmakers who carried their music and songs from place to place. Other songs came in from England and Scotland...but I can assure you that music hall did not exist for 95% of the population.
Yes, there was theatre in Dublin and Cork in which some of these songs were sung but for the most part they were to be heard at house dances and parties, pubs and ceilies.
I dont give the whole picture of course but perhaps other will add to this thread.
pj

I