Just another GR refugee. Other than that, I had a stroke in 2004, and read almost anything I can get my hands on, though I have a particular weakness for history, mystery, and historical fiction.
I've read 68 pages, which is the first two chapters, of the first volume of the history of the Hundred Years' War, and we haven't gotten the war started, as yet.
Chapter one looks at France as it was in 1328, on the death of her last Capet king (Charles IV). France is the richest territory in Europe. She is home to 16 million people. Paris has a population of at least 100,000 (double the size of London), and the cities in the French low countries ("Flanders") are some of the richest and most populous in northern Europe, grown rich on being the center of the wool trade.
The Capetian kings, however, only directly control a small portion of the land in their realm, mostly in the area around Paris. Most of what we would consider "France" is directly ruled by somebody else, mostly great aristocrats, some of the most important being the highest nobles of the land: previous kings' younger sons, or those sons' descendants - the royal dukes. They are jealous of their power, and the king has little power over their lands. There is no procedure for a French king to charge a general tax for anything except his own knighting, his eldest son's knighting, or his daughter's marriage. So he devalues the currency, instead.
France is rich in agriculture, but even so, the condition of the roads, and of transportation generally, mean that everyone, particularly the poor, are in danger of starvation if the roads are blocked long enough, or if the crops fail.
France, with its its large supply of great aristocrats, is justly proud of its knights (a king of France, if he truly needs to, might be able to summon 20 or 25 thousand of them), and the French are the most feared warriors in Europe.
Chapter two looks at the flip of the coin: England as it was at about the time of the ascension of Edward III (1327).
England has about a quarter of the population of France - 4 million. London is easily the largest city, and the only one worth comparing in size or importance to the cities of France, but it is only about half the size of Paris (about 50-60,000).
England, like France, has prospered agriculturally in the last century. However, unlike in France, the lands of its great aristocrats (all earls; Edward III won't create the first English duke for another decade) are usually divided into parcels all over the country.
Also, there is the concept that the king's law runs everywhere (he owns the entire kingdom, thanks to William the Conqueror; everyone else are just his tenants, to one degree or another), and there is a "common" law (unlike in France, where there are many, many different laws in force in different places).
There is also, to a growing extent, a common language: English. Even in the generation before Chaucer, the French of most of the English nobles is the French of "the school of Stratford-atte-Bowe." English is the language of most of the people, aristocrats included. (I assume Edward III himself has excellent French, however - his mother is a Capet.)
The English have a poor reputation as warriors, but the rest of Europe hasn't been paying much attention in the last half century or so, when the hobby of English kings has been invading (successfully) Wales and (not so successfully) Scotland. An English king can't call on as many knights as his French counterpart (5000 if he is very lucky), but the English, due to civil war at home, and from invading the neighbors, have developed mounted infantry (much cheaper than knights), and have found that men armed with the native longbow are much cheaper still.
To pay for a war, an English king, like a French one, might make a huge loan from his Italian banking family of choice (Edward I bankrupted several), pay for it in export taxes on wool (England's most valuable export, by a mile), or, if he is powerful and charismatic enough, getting support for a general tax through Parliament. Edward II, a weak king, had no pull with Parliament.
Edward III, even at 15, will be another story.