Roger in Sheffield, Its very common for folk airs to have several different versions of the lyrics and often to have lyrics that commemorate different events. After all the words always came first and were the reason why the song or ballad was written. Its interesting to note that the tune best known in Ireland as 'Boolavogue' is used in Australia for 'Moreton Bay', a song about the convict settlement that later became the city of Brisbane. The words of 'Moreton Bay'(sometimes 'The Convict's Lament') are said to have been written by one Frank MacNamara('Frank the Poet') an Irish convict who it is said, was related to Donnchadh Rua Mac Conmara, a well-known Gaelic poet of the Eighteenth century.