The Threshold is the common name for the lands which are part of Creation’s major land mass, between the shores of the Blessed Isle and the elemental poles. It is also sometimes used to refer exclusively to lands which are not part of the Realm.
The Realm does not directly rule any territories in the Threshold. Instead, the system of Satraps was established in which the Scarlet Empress would set up a relative (from the Scarlet Dynasty) that she personally chose to serve as an advisor to local governments which would remain free to continue their own legal system, culture and government as long as certain standards were met and tribute payments were made each year. In the days of the Empress, tribute payments were carefully set to be difficult but bearable.