User blog comment:FairyRaven/Fairy Tail Chapter 465: 400 Years, Review and Commentary/@comment-196.217.88.80-20151207124857/@comment-7418318-20151208005911

The thing with the Dragons being what triggered Freed's runes is still a valid theory.

Even before they time-jumped the Dragons were probably more then 66 years old (plus the 14 years between 777 and 784 brings them to 8ß), so they might well have triggered the runes either way.