Diarchy
From Wikipedia, the free encyclopedia
Diarchy (or dyarchy) is a society or an organization with two rulers on an equal standing. Diarchies are known from ancient Sparta, Rome, Carthage as well as from Germanic and Dacian tribes. Ranks in the Inca Empire were structured in moieties, with two occupants of each rank, but with different prestige, one hanan (upper) and one hurin (lower).
Examples of modern forms are the governments of Andorra and San Marino. The Montagu-Chelmsford reforms of British India prescribed a "dyarchy" of ministers who were individually responsible to the legislature.