Archaeological Society is a group of archaeologists whose goal is to preserve the archaeological sites of the kingdom of Fiore.
Key of the Starry Sky arc
The Archaeological Society, being interested in the clock and having heard rumors of Fairy Tail's journey, approaches Lucy's group and try to dissuade them. Upon learning her identity and her resolution in following her father's dying wish, Jean-Luc, the head archaeologist, who is familiar with Lucy's father, has a change of heart and uses his team's Magic to return Natsu to his original size.
Magic and Abilities
Dispelling Magic: The Archaeological Society showed some competence on Dispelling Magic, being able to erase Dan Straight's spell through a team spell, and reverting Natsu to his original size.