User blog comment:FairyRaven/Fairy Tail Chapter 366: 1000 Souls, Review and Commentary/@comment-92.37.55.98-20140109154110/@comment-7418318-20140109173152

He could have come back by means other than the Eclipse Gate.

The royal family might just not have known about this other means, or maybe it wasn't suited for going 400 years back (for which the Eclipse was constructed).

As much as I'd like to, we can't rule it out yet.