It's about the fair that was held in Donnybrook, Dublin, from the 13th through 19th centuries. The so-called fair was actually more of a riot - people fought mercilessly, hence the chorus of song. The government of Ireland tried relentlessly over the years to shut the fair down ("A license for leisure/whatever be the pleasure/the Council's always up in arms/to try and take it away"), however the license was never revoked until the late 1800s when it's licensee passed away. http://en.m.wikipedia.org/wiki/Donnybrook_Fair
It's about the fair that was held in Donnybrook, Dublin, from the 13th through 19th centuries. The so-called fair was actually more of a riot - people fought mercilessly, hence the chorus of song. The government of Ireland tried relentlessly over the years to shut the fair down ("A license for leisure/whatever be the pleasure/the Council's always up in arms/to try and take it away"), however the license was never revoked until the late 1800s when it's licensee passed away. http://en.m.wikipedia.org/wiki/Donnybrook_Fair