Like Henry V in 1415, Edward landed in Normandy in 1346 with the intent to conquer. However, although Jonathan Sumption explains that Edward soon abandoned the idea. Although he went on the take many important Norman towns, such as Caen -- and ultimately win a great victory at Crécy and take Calais, he was unable able to institute a permanent occupation. Three generations later, Henry V succeeded in taking Harfleur in 1415 and defeating the French at Agincourt. In 1417 he returned, landing in the same area that Edward III had 71 years before, and was able to conquer all of Normandy by 1420. What made this possible? Was it a change in military strategy? Developments in England's financial and political structures? The disarray of the French due to the Armagnac-Burgundian civil war?
Thanks in advance for any and all responses!!
I'll let someone else comment on the French side of things. Perhaps changes in siegecraft were important as well.
However, one key improvement for the Campaigns of Henry V compared to Edward was a comparatively more realistic strategic and logistical sense. Edward tended to base his campaigns out of Gascony, and look to force concessions from the french monarchy by land campaigns. (The 1346 campaign only landed in Normandy because of adverse weather.) This tended to be unfruitful because Gascony has difficult sea communications back to England, and French ports in Normandy could render them vulnerable to raiding and interdiction. Edward typically managed naval forces by creating a large armada thru impressing private ships every now and then to convoy his armies to Gascony. These large fleets took time to assemble and sail to Gascony, giving the French a strategic advantage (the French used a small professional fleet of italian galleys in addition to locally available shipping.) in all campaigns out of Gascony.
Henry's strategy of a direct cross channel campaign, based on securing the channel by besieging and occupying the major naval ports allowed him to exploit and follow up his successes in pitched battles. He had a more sustained naval effort based on a fairly complex series of renewed contracts with public ships, but privately run crews to maintain sea communications. This system proved fruitful but it was dismantled after Henry's death because the regency didn't have the political capacity to raise funds necessary to maintain it. Because Henry had stable communications by sea, his armies could press home field victories and lay successful sieges.
The source for this naval and strategic comparison is N.A.M. Rodger's "The Safeguard of the Sea: A naval history of Britain 660-1649"