User blog comment:FairyRaven/Fairy Tail Chapter 319: The White Knight, Review and Commentary/@comment-4829046-20130215153705/@comment-121.54.8.130-20130216003912

the GMG must be in X792:

Tenrou Island disappeared Dec X784, after 7 years it reappeared so Dec X791.. Some members had 3 months training and the GMG takes place July 1 to July 7, so it must be X792..