“Over the course of a century” is different from 900 years. :-). Now, you’re within the bounds of critical scholarship. Of course, there are disputes within the scholarship community on this. The gospels are dated (depending on who you ask) to between AD (or CE) 50 to 100. A small minority will date John after 100. But virtually all scholars will date at least seven of Paul’s epistles to within 20-30 years from Jesus’ time. I Corinthians, for example, was written in the early 50s.