Source : Webster's Revised Unabridged Dictionary (1913)

Heptarchy \Hep"tarch*y\, n. [Hepta- + -archy: cf. F.
   heptarchie.]
   A government by seven persons; also, a country under seven
   rulers.

   Note: The word is most commonly applied to England, when it
         was divided into seven kingdoms; as, the Saxon
         heptachy, which consisted of Kent, the South Saxons
         (Sussex), West Saxons (Wessex), East Saxons (Essex),
         the East Angles, Mercia, and Northumberland.