The song of 'The Aretusa' originally appeared in a small opera or musical entertainment called 'The Lock and Key', which was acted in 1796. The Princess Royal was composed for the eldest daughter in Carolan's time of The MacDermott Roe of Coolavin. It is perhaps worth mentioning that there is an English folk song, of fairly wide distribution in England which is entitled 'The Princess Royal' but has no connection with Carolan's melody.