The most accurate meaning of this term would be a situation where numerous local lords are powerful and autonomous, but there is one among them who commands disproportionately large resources and is capable of raising overwhelmingly powerful military forces, either directly from his own personal domains or from his loyal vassals.
In this situation, any lord who defies the monarch openly can be subdued by sheer military force, so if the monarch successfully advertises his military power and his commitment to lash out whenever provoked, there can be a stable equilibrium where local lords find it in their best interest to be loyal vassals, profess allegiance, and pay their tribute in a timely manner—and otherwise be left alone to rule their fiefs. Another factor that can strengthen this equilibrium is if the monarch’s military power provides protection against an external threat that is too powerful for the lords to handle individually; in such situations, the monarch can be more of a coalition leader than overlord.
Clearly, such an equilibrium is unstable for many reasons. External military threats can disappear, a strong monarch can be succeeded by a weak one who won’t be able to insist on his supremacy credibly, local lords can become powerful to the point where defiance seems tempting, a neighboring ruler can offer a better deal for those who switch allegiance to him, several lords can form a coalition too powerful to subdue, and so on. The classic example is the history of the Frankish Empire and the Holy Roman Empire. Occasional exceptionally capable and powerful rulers were able to assert strong personal authority, but their heirs would regularly fail to uphold it.
The most accurate meaning of this term would be a situation where numerous local lords are powerful and autonomous, but there is one among them who commands disproportionately large resources and is capable of raising overwhelmingly powerful military forces, either directly from his own personal domains or from his loyal vassals.
In this situation, any lord who defies the monarch openly can be subdued by sheer military force, so if the monarch successfully advertises his military power and his commitment to lash out whenever provoked, there can be a stable equilibrium where local lords find it in their best interest to be loyal vassals, profess allegiance, and pay their tribute in a timely manner—and otherwise be left alone to rule their fiefs. Another factor that can strengthen this equilibrium is if the monarch’s military power provides protection against an external threat that is too powerful for the lords to handle individually; in such situations, the monarch can be more of a coalition leader than overlord.
Clearly, such an equilibrium is unstable for many reasons. External military threats can disappear, a strong monarch can be succeeded by a weak one who won’t be able to insist on his supremacy credibly, local lords can become powerful to the point where defiance seems tempting, a neighboring ruler can offer a better deal for those who switch allegiance to him, several lords can form a coalition too powerful to subdue, and so on. The classic example is the history of the Frankish Empire and the Holy Roman Empire. Occasional exceptionally capable and powerful rulers were able to assert strong personal authority, but their heirs would regularly fail to uphold it.