I learned most of my British English as a lad of thirteen in 1968–69 and one of twenty in 1975–76, during which (academic) years I lived in Sussex. As a Yank (I think that at least is still a current usage, at least in schoolboy register), I then had to get used to the term Christian name for what I had always called simply my first name. As I approach my first visit to England in some sixteen years, I wonder if it is time to unlearn that lesson, what with the new London mayor and all. Does this usage garner odd looks in today’s more multicultural England? Will it perhaps mark the user as a UKIP (or, by transatlantic extension, Trump) sympathiser?
Ngram suggests decline since 1968 but by no means to the point of vanishing. I can find no previous EL&U question on this, though there is some relevant discussion here.
Best Answer
The decrease in usage of the expression "Christian name" may be a reflection of the cultural changes that happen through time. It, however, didn't necessarily refer to religion, according to the following extract:
(Wikipedia)
Usage notes:
From The AHD:
From The Collins Dictionary: