This is how my ( and probably also your ) favourite style of dancing started:
Evidences seems to suggest that solo dances were the creation of dancing masters of the 18th/ 19th centuries. All references to irish dances in literature up to the beginning of the 18th century deal only with round and long dances. The dancing master was a very important person in rural Ireland and he commanded the greatest respect. His dress was colourfull and he travelled the country from village to village in the company of a piper or a blind fiddler.

There would be great excitement in a village when the dancing master arrived, as it meant that there would be music and dancing for several weeks. He might stay in one farmers house or in a different house each night. Each dancing master had his own district and never encroached on the territory of someone else.
It is said that the dancing master received a fee of a sixpence from his pupils, with the musician getting about half this amount.
Dancing masters would challenge eachother at fairs or similar events and hold a dancing contest in public. Around 1800, Cork, Kerry and Limerick were renowned for their dancing masters.
There was a time when men and women did not dance the same steps/dances. The old dancing masters thaught women steps of a lighter and simpler caracter. Steps with a "trebble" or "batter" were traditionally saved for men.