The Nation of Equestria was certainly vast, there was no question at the time, that it was the size of most of the planet. Sure ya had Griffon, dragon, and other kingdoms all around, until a note appears in a completely foreign language. A magical spell translated it easily, revealing a simple query about if anyone was out there. Twilight and friends set out to find the land beyond the Zebra kingdom.

Meanwhile in the grand nation of Legacy, another great evil had been sealed away and the power of the Holy star and Guiding light had returned to normal across the land. The heroes of this world rest happily at ease, until Astea Of the Guiding light tells them of the destruction of 'the barrier' and days later a ship is seen Sailing in their direction. Wein king of the East Land of Legacy, sets out to great their new guests.
Note: this is a crossover fantasy story, taking the idea of a land of ponies on one side of the planet, while a Sonic Adventure esq world of humans, elves, and anthropomorphic animals lived on the other. Hyrule, Mobius, Legendra, and probably the Mushroom kingdom make up the land of Legacy.