Aybara originally tried to suppress the use of this, but combined with the requirement of a figure of authority, the raising of the banner of Manetheren, and the encouragement of his wife Faile, the title Lord Perrin persisted.
When Perrin met with Elayne Trakand, Queen of Andor, it was decreed that the Two Rivers would be ceded to the Dragon Reborn, who would be persuaded to appoint Perrin as his Steward. The Two Rivers would be exempt from Crown taxes, instead paying into a fund that would be held "against the return of the Lord Dragon." These taxes could be dipped into by the Steward of the Two Rivers as required, in effect making the Two Rivers it's own Kingdom.
The Two Rivers remained part of Andor, but the unique nature of the situation is reflected by it holding the official rank of High Lord - specifically, that the Lord of the Two Rivers will outrank other Lords and Ladies of Andor.
Coat of Arms
The Coat of Arms of the Two Rivers is assumed to be the Red Wolfhead on a White field.