Hi Clarah,
James Clarence Mangan (JCM), born in Fishamble Street, Dublin, 1st May, 1803, and died in Dublin 20 June, 1849.
Clarence (nom de plume from 1820's onward) Mangan's father was indeed James Mangan also, a grocer, and now we have him from Shanagolden Yale, Co Limerick.
Yes, Catherine Smith was his mother and also he reveals in his autobiography that he had two brothers (some reckon one older and one younger, whereas others reckon John b. 1804 and William b. 1808) and one younger sister (some reckon she died young).
Catherine Smith was from a farming family from Kiltale, Co. Meath. However, her grandfather, John Smith, was a publican in Fishamble Street and it appears that JCM's father and Catherine Smith married in April 1798 then moved to Dublin in 1801 where they set up a business already generated by Catherine's aunt in Dublin.
I'm still reviewing my other Mangan books I've collected over the years for more clues.
My family line on my mother's side is that her grandfather was James "Valentine" Mangan (b. 14 feb 1875 - dublin) who married in 1900 a Liverpudlian (Mary Josephine Walker b.1878). His father was Andrew Mangan (b. circa 1850) , so we believe Andrew was possibly a nephew of James Clarence Mangan (JCM).... still to be proven by me though. My Grandmother always claimed the Mangan's moved to "Royal Meath" and hence always loved the lyrics of the Foggy Dew song - "From the plains of Royal Meath". So I have some more clues to go on. Also, JCM did die in the Meath Hospital, Dublin (ironically).
Unfortunately, my relative Frank Crummey is busy preparing for a book launch in Dublin for 9th March this year and hasn't responded with what he's unearthed with his family's link to JCM. I'll keep the forum posted of his results when I receive them probably after the book launch.
Stephen.