May seem a strange question but was it common for people to change their christian name...?
I have in my tree Patrick Carr (b c1856) m Catherine Kelly (b c1858) in 1878. I have them in the 1891 census with children James (b1879), John (b1881),... but no mention of them in the 1881 census. However, I did find:
Nathaniel Carr (b c1857), Catherine (b C1859), James (b 1878) and John (b1881) and no mention of Nathaniel Carr in 1891 census. No sign of a deceased Nathaniel in the intervening 10 years either. Could he have changed his name? If so why? He was Patrick in 1878 (marriage) and again in 1891 if Nathaniel is the same person...

Any suggestions welcome!
Damien
PS On the marriage certificate Patrick's father is listed as James Carr, mariner, deceased. I have a James (mariner) but no son Patrick I can find or Patrick but not father James (mariner)!
PPS Prior to the marriage (according to the marriage certificate) both Patrick and Catherine lived in Sawney Pope St in Liverpool. Does anyone know of any records for specific streets...?