Has anybody ever heard of this character from Castlebar: John Hennen (1779-1828)was born on 21 April 1779, the younger son of James Hennen, a surgeon who practised at Castlebar, County Mayo, and the scion of an Anglo-Irish family endowed with lands by Cromwell. Educated locally and in a boarding-school in Limerick, he was apprenticed to his father and availed of the opportunity to watch operations at the County Infirmary.
Hennon had a distinguished career as a military surgeon and was author of two books published posthumously
Principles of Military Surgery(1829)
Medical Topography of the Mediterranean,(1830)

He died in Gibraltar in 1828
A monumental tablet to the surgeon’s
memory was erected by public subscription
in King’s Chapel, Gibraltar.