The professionals fought in companies whose leaders took oaths of homage and fealty to a prince, but under contracts that were not hereditary and usually for a term of months or years. The fief was embedded in the customary law of western Europe, and the incidents of feudalism, such as wardship and marriage, escheat and forfeiture, continued to flourish after feudal military service died out. In England feudal tenures were abolished by statute in 1660, but they lingered on in parts of the Continent until the customary law was replaced by Roman law, a process completed by Napoleon. Roman law substituted other legal notions for feudal ones on the Continent, but in England the common law continued to be basically feudal law. Wherever English people settled in the modern era, they took their common law with them and thus established feudal principles all over the world.
English constitutionalism is fundamentally feudal, based on the contract theory of government.
When John Locke wrote his treatises on government in the 17th century, he was seeking to generalize for all persons the feudal contract that limited the rights of the suzerain over his vassals and retained for them the German warrior's independence. The U.S. Declaration of Independence was a classic act of feudal defiance, as the Continental Congress enumerated the tyrannical acts of the king and declared the colonists no longer bound by their allegiance to him. In sum, feudal ideas were important to the political development of Western civilization, reconciling authority with liberty by way of contract.