User blog comment:Natsu11/Zeref and Natsu?/@comment-211.26.201.90-20131223105117/@comment-1359322-20131223111200

No one forgot about that, but since it wasn't explained fully, it isn't suitable to use that as an example to say that Natsu was from 400 years ago or anything close to that theory. There are also theory that the reason why they couldn't past is because of their Dragon Slayer magic.