User blog comment:FairyRaven/Fairy Tail Chapter 465: 400 Years, Review and Commentary/@comment-71.222.52.171-20151208050347/@comment-1776824-20151208091134

If Zeref didn't stick around, Layla would not have opened the Eclipse Gate on July 7, X777 to 100% ensure that the Dragon Slayers arrived at the intended time period. Zeref wanted to make sure at all costs that the time periods were undoubtedly connected and that everything went according to his plan.

And Anna honestly isn't that relevant. She opened the gate in the past; if there was anything more to be said on that, I'm sure it would have been mentioned. .-.