A single ruler sitting on a throne has been a common form of political organization. A kingdom is a state or territory ruled by a king or queen, usually on a hereditary basis and often legitimized by tradition or sacred authority.

Kingdoms have ranged from small city-centered polities to extensive realms incorporating diverse regions. Administration might rely on nobles, officials, or local intermediaries. Succession rules—primogeniture, election among royal kin, or other customs—shaped stability and conflict.

Many kingdoms were absorbed into larger empires or transformed into constitutional monarchies or republics. Others persist as modern states with residual or active royal institutions. The history of kingdoms illustrates both the durability of monarchical ideas and the variety of ways authority has been organized around a royal center.

• Territory ruled by a king or queen
• Usually hereditary
• Varies widely in size and administration
• May evolve into other political forms