Iron triangles result in a three-way alliance, the stable alliance that is sometimes called a subgovernment because of its durability, impregnability, and power to determine policy.

The Peloponnesian War 431-404 BCE was a struggle between Athens and its empire and the Peloponnesian League led by Sparta.

Athens, its apsirations buoyed up by the empire it established after seeing off the Persian threat, began interfering in disputes outside its empire, bringing it into conflict with the city-states of the Peloponnesian League, especially Corinth, over Corcyra and Potidaia. Athens went too far in imposing destructive trade restrictions on its neighbour Megara, a member of the Peloponnesian League. The League demanded lifting of the restrictions. Athens, convinced of the impregnability of its fleet and walled city, and the financial support it drew from its empire, refused compromise and war ensued.

Neither side foresaw a 27-year war which brought in and devastated the Greek world from Sicily to Asia Minor.

The quality or state of being strong; ability to do or to bear; capacity for exertion or endurance, whether physical, intellectual, or moral; force; vigor; power; as, strength of body or of the arm; strength of mind, of memory, or of judgment., Power to resist force; solidity or toughness; the quality of bodies by which they endure the application of force without breaking or yielding; -- in this sense opposed to frangibility; as, the strength of a bone, of a beam, of a wall, a rope, and the like., Power of resisting attacks; impregnability., That quality which tends to secure results; effective power in an institution or enactment; security; validity; legal or moral force; logical conclusiveness; as, the strength of social or legal obligations; the strength of law; the strength of public opinion; strength of evidence; strength of argument., One who, or that which, is regarded as embodying or affording force, strength, or firmness; that on which confidence or reliance is based; support; security., Force as measured; amount, numbers, or power of any body, as of an army, a navy, and the like; as, what is the strength of the enemy by land, or by sea?, Vigor or style; force of expression; nervous diction; -- said of literary work., Intensity; -- said of light or color., Intensity or degree of the distinguishing and essential element; spirit; virtue; excellence; -- said of liquors, solutions, etc.; as, the strength of wine or of acids., A strong place; a stronghold., To strengthen.

The quality or state of being strong; ability to do or to bear; capacity for exertion or endurance, whether physical, intellectual, or moral; force; vigor; power; as, strength of body or of the arm; strength of mind, of memory, or of judgment., Power to resist force; solidity or toughness; the quality of bodies by which they endure the application of force without breaking or yielding; -- in this sense opposed to frangibility; as, the strength of a bone, of a beam, of a wall, a rope, and the like., Power of resisting attacks; impregnability., That quality which tends to secure results; effective power in an institution or enactment; security; validity; legal or moral force; logical conclusiveness; as, the strength of social or legal obligations; the strength of law; the strength of public opinion; strength of evidence; strength of argument., One who, or that which, is regarded as embodying or affording force, strength, or firmness; that on which confidence or reliance is based; support; security., Force as measured; amount, numbers, or power of any body, as of an army, a navy, and the like; as, what is the strength of the enemy by land, or by sea?, Vigor or style; force of expression; nervous diction; -- said of literary work., Intensity; -- said of light or color., Intensity or degree of the distinguishing and essential element; spirit; virtue; excellence; -- said of liquors, solutions, etc.; as, the strength of wine or of acids., A strong place; a stronghold., To strengthen.

The quality or state of being strong; ability to do or to bear; capacity for exertion or endurance, whether physical, intellectual, or moral; force; vigor; power; as, strength of body or of the arm; strength of mind, of memory, or of judgment., Power to resist force; solidity or toughness; the quality of bodies by which they endure the application of force without breaking or yielding; -- in this sense opposed to frangibility; as, the strength of a bone, of a beam, of a wall, a rope, and the like., Power of resisting attacks; impregnability., That quality which tends to secure results; effective power in an institution or enactment; security; validity; legal or moral force; logical conclusiveness; as, the strength of social or legal obligations; the strength of law; the strength of public opinion; strength of evidence; strength of argument., One who, or that which, is regarded as embodying or affording force, strength, or firmness; that on which confidence or reliance is based; support; security., Force as measured; amount, numbers, or power of any body, as of an army, a navy, and the like; as, what is the strength of the enemy by land, or by sea?, Vigor or style; force of expression; nervous diction; -- said of literary work., Intensity; -- said of light or color., Intensity or degree of the distinguishing and essential element; spirit; virtue; excellence; -- said of liquors, solutions, etc.; as, the strength of wine or of acids., A strong place; a stronghold., To strengthen.