Think you can forget about the John Shannon in Denmark Street.
It looks like John Shannon was a sponsor in 1873 to a girl living at 25 Whitefriar St., it was probably a tenement so it's unlikely he rented a house on Denmark st. all on his own.
http://churchrecords.irishgenealogy.ie/churchrecords/details/61eb320076436
Could be the son or the father I guess.
A Margaret Shannon was also a sponsor in 1860, so either she was still alive or this is a daughter.
http://churchrecords.irishgenealogy.ie/churchrecords/details/7b93000330726
Thanks, Just reading my Grandfather's notes and all it states about John Shannon's (the elder) wife is, "Mary O'Sullivan (1830-1856) married John Patrick Shannon before she was 20 and died around 1856, aged 26 when son John was an infant. Nothing more is known about her." I've never been too convinced about the accuracy of his recollections concerning someone he never met and so many years after the event.
I've never been able to trace her, though another search based on recent access to further records is on my 'to-do' list. Not even sure what her name actually was, though John Shannon (the younger) named his first child, born in 1875, Mary Margaret- and there might be the answer! The appearance of a Margaret Shannon as Godmother to someone in 25 Whitefriars St in 1873 is interesting though.
