By the end of the march across Normandy in 1346, Edward had accepted that he was not going to be able to hold French territory. But he had a clear objective - Calais. Philip meanwhile now hoped that the Scots would invade an empty, defenceless England and Edward would have to abandon his plans and rush back home.
The Siege of Calais
Calais in 1346 was not a big and important town, not a particularly important trading centre - but it had two key factors that made it significant. It was of course very close to England; and it had a massive and well designed fortifications. So off Edward set to Calais.
It was a tough target, completely surrounded by water. On the north die was a harbour, separated from the town by a moat and wall
In the North West was the castle with a circular keep and bailey, defended by an independent system of moats and curtain walls
Outside the town was an expanse of bleak marshland crossed by lots of small rivers and shifting causeways. The ground was too soft for siege engines or mining
Pretty soon, outside Calais sat a new, temporary town of Villeneuve-la-Hardie, or 'Brave new town'. Given that the English army was now 34,000 strong, this was a town bigger than any English town outside London. Edward had prepared for the long game, know that assault was almost certain to fail. But the defences constructed by the besiegers made it almost impossible for the French to shift them, which Philip found to his cost.
The siege took 11 months, and was successful at least in part because of the surge of public support after the victory at Crecy. Eventually, you get Froissart's superb theatre of the surrender. The negotiation between Walter Manny and the French commander, Jean de Vienne; Edward's implacable determination to make the town suffer; the 6 burghers, bareheaded and wearing halters, the sacrificial lambs to assuage the fierce king's anger; and the mercy of Phillipa, throwing herself onto her knees in front of Edward to win his mercy. The message was pretty clear - the King of England decided the fate of French subjects, hate it or loathe it.
The Battle of Neville's Cross, 17th October 1346
King David of Scotland marched south with a well prepared invasion, heart full of glee to have England, as he thought, at his mercy. Trouble is, he rather messed about - taking time to capture castles on the border that he could have easily left alone. Which gave the English wardens of the Nothern Marches - Henry Percy and Ralph Neville - and the Archbishop of York time to gather an army. The tradition was that all the lands north of the river Trent were to be devoted to beating off the Scots.
William Douglas, the hugely successful Scottish warrior, met the English forces in fog outside Durham. He fell back after a bit of a mauling, and David chose his ground and waited. Both sides faced each other over ground broken by stone walls both waited for the other to attack, since that was the pathway to victory it seemed, after Crecy. Eventually, the English advanced some archers and started tormenting the Scots. David lost his patience and attacked - now over the very ground he'd chosen as perfect for defence. Not good. The scots were defeated and David found and captured under a bridge, and lobbed into the Tower of London. The whole thing was a disaster for the Scots - and England were to have peace for many years.
The Battle of La Roche Derrien, 18th June 1347
In 1346/7, Charles of Blois was able to ride roughshod over Thomas Dagworth and the English in Brittany with a much larger army. Eventually he tipped up at La Roche Derrien - Dagworth's only port in northern Brittany. Charles hoped to lure Dagworth into attacking, with a far smaller army, so that Charles could destroy him.
Dagworth took the bait - with just 700 men to the 5,000 French, he attacked in the middle of the night. He'd noticed that Charles's army was in 4 segments, separated by marsh and wood land, so maybe he could beat each section, helped by a surprise attack.
Charles was not surprised. And so was waiting in full armour when Dagworth and his men crept into camp. And so it was going badly for Dagworth. But then the castle sallied, and suddenly Charles was in trouble, and captured in a windmill. And then yes, Dagworth beat each segment of the French army in turn.
Charles meanwhile went off to join David in the Tower of London, and his cause in Brittany lay in ruins.