When DID the races separate? (Theorycrafting)

[reesespuffed 28]

People always wonder why they did but im thinking when is exactly the timeframe? It was long enough for a pegasus royal family to happen but not long enough for the tribes to really get too comfortable and be unwilling to change no matter what. How did argyle even know who twilight was? did he have parents who knew or found books? Also the unicorns do know what magic is so the concept of that isnt lost to time. I guess this means a few centuries so the pegasus royalty forms but not enough for fim to be truly forgotten

[Courageous Thunder Dash 7,828]

It would've had to be when Twilight had no other choice...we don't really know why yet. There's supposed to be a special that explains the timeframe just before the G5 movie.