From Burning Wiki
Burning Magic The Gathering: Regents
A Regent wields the power of the land. Emperors use the rules for Regents, once properly confirmed.
Becoming a Regent: To become a Regent, one must crowned by one who derives their power from the land, one whose power comes from goods, and one whose power is founded on the loyalty of others. Once one has the support of these three, and there is no other Regent in the same region, one becomes a Regent.
A Regent controls one or more Provinces. Each province is either Black (sinister, swamp, crooked), Red (barbaric, mountain, waring), Blue (cunning, island, cultured), Green (harmony, forest, nature), or White (holy, plains, noble). Tap (use) a Province to allow you to use Circles to call a creature of that type, and a +1D to the test per Province (Land) you Tap. A Tapped Province cannot be used again until the next session, when all Provinces Untap.
Once you are confirmed as Regent, you may conquer other provinces to expand your domain, without having to be crowned again.