User blog comment:Zathronas/Speculative author: The Grimm and the next season/@comment-25405817-20141011170105/@comment-24218038-20141011171318

Actually there is evidence of that.

''Weiss: Atlas developed the Cross Continental Transmit System to allow the four kingdoms to communicate with one another. It was their gift to the world after the Great War. ''

It seemed to be their only form of communication short of courrier.