The Convocation of Creatures is a special meeting held rarely within Equestria. The purpose of the event is to help the races of Equestria come closer together, and to better understand eachother.
History
The last one, according to Inkwell, took place 753 years ago.
Season 8
The current Convocation was attended by Twilight Sparkle, some of the Harmony Gems, along with representatives for the Zebras, Dragons, Yaks, Deer, even the Changelings in form of Thorax.