Christian name vs aftername

Christian name

noun
  • An English given name, particularly for ethnic Chinese who usually have a separate Chinese name. 

  • Any forename. 

  • A first name formally given to a child at a Christian baptism. 

aftername

noun
  • A designation which comes after a name, similar to, yet not necessarily equivalent to one's last name 

How often have the words Christian name and aftername occurred in a corpus of books? (source: Google Ngram Viewer )