From Hume's History of England.
There is not a reign among those of the ancient English monarchs, which deserves more to be studied than that of Edward III., nor one where the domestic transactions will better discover the true genius of that kind of mixed government, which was then established in England. The struggles with regard to the validity and authority of the Great Charter were now over: the king was acknowledged to lie under some limitations: Edward himself was a prince of great capacity, not governed by favorites, nor led astray by any unruly passion, sensible that nothing could be more essential to his interests than to keep on good terms with his people: yet, on the whole, it appears that the government at best was only a barbarous monarchy, not regulated by any fixed maxims, or bounded by any certain undisputed rights, which in practice were regularly observed. The king conducted himself by one set of principles, the barons by another, the commons by a third, the clergy by a fourth. All these systems of government were opposite and incompatible: each of them prevailed in its turn, as incidents were favorable to it: a great prince rendered the monarchical power predominant; the weakness of a king gave reins to the aristocracy; a superstitious age saw the clergy triumphant; the people, for whom chiefly government was instituted, and who chiefly deserve consideration, were the weakest of the whole.
In contrast to his father, Edward II, Edward III acquired the skill set necessary to thrive in his position. His conquests of the French sat the course of that long-standing rivalry.
An interesting point is that as a conqueror he had to give more concessions to the people -- the feudal system not providing for any efficient means of taxation and supplying forces.
It is remarked by an elegant historian, that conquerors though usually the bane of bunian kind, proved often, in those feudal limes, the most indulgent of sovereigns: they stood most in need of supplies from their people; and not being able to compel them by force to submit to the necessary impositions, they were obliged to make them some compensation, by equitable laws and popular concessions.
This remark is, in some measure, though imperfectly, justified by the conduct of Edward III. He took no steps of moment without consulting his parliament, and obtaining their approbation, which he afterwards pleaded as a reason for their supporting his measures. The parliament, therefore, rose into greater consideration during his reign, and acquired more regular authority, than in any former time; and even the house of commons, which, during turbulent and factious periods, was naturally depressed by the greater power of the crown and barons, began to appear of some weight in the constitution.
Implications about the Great Charter (which we, more pretentious than Hume, refer to the Magna Carta) and how legal precedents were looked at during feudalism.
Edward granted above twenty parliamentary confirmations of the Great Charter; and these concessions are commonly appealed to as proofs of his great indulgence to the people, and his tender regard for their liberties. But the contrary presumption is more natural. If the maxims of Edward’s reign had not been in general somewhat arbitrary, and if the Great Charter had not been frequently violated, the parliament would never have applied for these frequent confirmations, which could add no force to a deed regularly observed, and which could serve to no other purpose, than to prevent the contrary precedents from turning into a rule, and acquiring authority. It was indeed the effect of the irregular government during those ages, that a statute which had been enacted some years, instead of acquiring, was imagined to lose, force by time, and needed to be often renewed by recent statutes of the same sense and tenor.
Edwards III's need gain support (and competence in winning it) even extended to trying to placate the House of Commons -- and one would imagine real issues facing the non-nobility. And so:
The nobility were brought to give their promise in parliament, that they would not avow retain, or support any felon or breaker of the law; yet this, engagement, which we may wonder to see exacted from men of their rank, was never regarded by them. The commons make continual complaints of the multitude of robberies, murders, rapes, and other disorders, which, they say, were become numberless in every part of the kingdom, and which they always ascribe to the protection that the criminals received from the great.
So much for chivalry. The real truth is that barons made use of criminals to destabilize rivals, or even as an extra income source.
Next, Hume offers some commentary about the clergy:
There were strong reasons, which might discourage the kings of England, in those ages, from bestowing the chief offices of the crown on prelates and other ecclesiastical persons. These men had so intrenched themselves in privileges and immunities, and so openly challenged an exemption from all secular jurisdiction, that no civil penalty could be inflicted on them for any malversation in office; and as even treason itself was declared to be no canonical offence, nor was allowed to be a sufficient reason for deprivation or other spiritual censures, that order of men had insured to themselves an almost total impunity, and were not bound by any political law or statute. But, on the other hand, there were many peculiar causes which favored their promotion. Besides that they possessed almost all the learning of the age, and were best qualified for civil employments, the prelates enjoyed equal dignity with the greatest barons, and gave weight by their personal authority, to the powers intrusted with them; while, at the same time, they did not endanger the crown by accumulating wealth or influence in their families, and were restrained, by the decency of their character, from that open rapine and violence so often practised by the nobles. These motives had induced Edward, as well as many of his predecessors, to intrust the chief departments of government in the hands of ecclesiastics; at the hazard of seeing them disown his authority as soon as it was turned against them.
Speaking of the church, Hume reports that the English already had a growing "anti-Rome" streak even at this early date:
The laity at this time seem to have been extremely prejudiced against the papal power, and even somewhat against their own clergy, because of their connections with the Roman pontiff. . . Men who talked in this strain, were not far from the reformation: but Edward did not think proper to second all this zeal. Though he passed the statute of provisors, he took little care of its execution; and the parliament made frequent complaints of his negligence on this head. He was content with having reduced such of the Romish ecclesiastics as possessed revenues in England, to depend entirely upon him by means of that statute.
Interesting aside about "the Flemish," of the time, at which I hit the books (searched Wikipedia) and think Hume means Ghent operating as a city-state:
As the Flemings were the first people in the northern parts of Europe that cultivated arts and manufactures, the lower ranks of men among them had risen to a degree of opulence unknown elsewhere to those of their station in that barbarous age; had acquired privileges and independence, and began to emerge from that state of vassalage, or rather of slavery, into which the common people had been universally thrown by the feudal institutions. It was probably difficult for them to bring their sovereign and their nobility to conform themselves to the principles of law and civil government, so much neglected in every other country: it was impossible for them to confine themselves within the proper bounds in their opposition and resentment against any instance of tyranny: they had risen in tumults: had insulted the nobles: had chased their earl into France; and delivering themselves over to the guidance of a seditious leader, had been guilty of all that insolence and disorder to which the thoughtless and enraged populace are so much inclined, wherever they are unfortunate enough to be their own masters.
This seems to fit the historical pattern of republic that breaks down into personal rule:
Their present leader was James d’Arteville, a brewer in Ghent,who governed them with a more absolute sway than had ever been assumed by any of their lawful sovereigns: he placed and displaced the magistrates at pleasure: he was accompanied by a guard, who, on the least signal from him, instantly assassinated any man that happened to fall under his displeasure: all the cities of Flanders were full of his spies: and it was immediate death to give him the smallest umbrage: the few nobles who remained in the country, lived in continual terror from his violence: he seized the estates of all those whom he had either banished or murdered; and bestowing part on their wives and children, converted the remainder to his own use. Such were the first effects that Europe saw of popular violence, after having groaned, during so many ages, under monarchical and aristocratical tyranny.