Qui ? quoy ? comment ? à qui ? pourquoi ?
Passez, presens, ou avenir[1]
For Charles VII of France, the year 1444 was one of contrasts.
Let us begin with the more triumphant events in the spring. The recent successes of France against the perfidious English were vindicated in the signing of the Treaty of Tours on 22 May, 1444. With the defection of no-longer-perfidious-but-still-very-suspicious Burgundy from the English side to the French following France's military victories and the predominance of the English peace party in the court of the less-than-stalwart King Henry VI, Charles could negotiate from a position of strength, something unheard of in recent French history.

Charles VII, looking ecstatic over recent French successes.
Under the terms of the treaty, Henry VI would marry Margaret of Anjou, Charles' niece, daughter of his brother-in-law René of Anjou, titular King of Naples, actual Duke of Bar and Anjou and, by marriage, Lorraine.[2] In exchange, Henry would return Maine to the French. In addition, there would be a truce for 21 months, which was sure to be a prelude to eternal peace and brotherhood between the two countries.

Henry VI, definitely not looking like he is going to have numerous mental breakdowns.
Having put a pause on his problems in the west (though making a lot of doughty Englishmen quite bothered, as latter events will demonstrate), Charles turned towards the east. The nebulous borderlands of France and the Holy Roman Empire were where Charles' domestic and international priorities came to a point. It was here that Philip the Good, Duke of Burgundy, once more a “loyal” vassal of French crown, was engaging in a lot of land-acquisition by various means.[3] Checking the duke's ambitions would be necessary for the long-term stability of France, which is where Charles' international diplomacy bore fruit.

Philip the Good, filled with feelings of warm fealty to his God-given monarch.
The Valois had cultivated an alliance with the Habsburgs. Indeed, Charles had arranged the betrothal of his eldest daughter, Radegonde[4], to Sigismund, Duke of Further Austria, currently under the tutelage of King Frederick of the Romans. It was this alliance that would draw the French into the hot mess that was the Upper Rhine.

Radegonde of France and her improbable headgear.
To call the state of affairs in this mountainous realm “chaotic” would be an understatement. Comprised of a patchwork of nominally-independent cities, bishoprics and counties of various loyalties and tangled alliances, there were three main affinities to be found at the time: the Confederacy (currently comprised of that cantons of Bern, Lucerne, Uri, Schwyz, Unterwalden, Glarus and Zug), the Habsburg bloc (comprised of the ex-Confederate canton of Zurich, the Margraviate of Alsace, Duchy of Further Austria and other nobility), and the sort-of/kind-of neutral and peace-mediating Council of Basel and its “pope,” Felix V, né Duke Amadeus VIII of Savoy.
At present, there was quite bit of warfare going on throughout the region. Why? For the reason, we must go back to 1436, when the aged Count Friedrich VII of Toggenburg, possessor of huge tracts of land, had the discourtesy of not only dying without heirs but also without a will.

Friedrich dying, invalid and intestate.

The aforementioned huge tracts of land.
Seeing all this lovely land up for grabs, Burgomaster Rudolf Stüssi of Zurich, then a part of the Confederacy, claimed them. The cantons of Schwyz and Glarus, supported by the other cantons, made counter-claims. Thereupon, in 1438, Zurich occupied the disputed areas and cut off the grain supply to their rivals. In response, the Confederacy voted to expel Zurich in 1440. In response to the response, Zurich made an alliance with King Frederick, who was eager to take advantage of the situation to reclaim his families' ancestral lands in the Aargau and show these Confederates what for.
As the war went on, things were not looking good for Zurich and the Hapsburgs, with a string of defeats by Confederate forces, including the rather dramatic Battle of St. Jakob an der Sihl on 22 July, 1443, wherein the commander of Habsburg forces, Albrecht Freiherr von Bussnang, was killed behind the altar of the St. Jakob chapel and Rudolf Stüssi was slain while defending the bridge over the Sihl, preventing the siege of Zurich.[5] Efforts by Pope Felix and the Council of Basel to mediate a peace ultimately failed, leading to further escalation, including the sieges of Zurich and Farnsburg in the Aargau by Confederate forces.

The last stand of Rudolf Stüssi and his axe.
It was these defeats that compelled Frederick to call in his ally Charles to intervene and he sent William von Hachberg-Rötteln, governor of Habsburg lands in Alsace and Further Austria, to make his case. Charles, seeing an opportunity to aid his ally and defend the patrimony of his soon-to-be son-in-law Sigismund (not to mention cause some disruption among pro-Burgundian elements in that area), agreed. While he himself was involved with the upcoming siege of Metz on behalf of René of Anjou (in order to sow some disruption among pro-Burgundian elements in the area), he had quite a lot of unemployed mercenary types, known écorcheurs (“flayers”) or Armagnacs, left over from the Burgundian-Armagnac feud and the war with the English, infamous for their tendency to rob and slaughter everything in sight.
In addition, Charles had something more dangerous and capricious to assuage and keep occupied lest it cause him great harm and disaster than thousands of unemployed, brutal soldiers of fortune: his querulous, rebellious, vulgar and cunning heir, the Dauphin, Louis Valois. This decision would lead to much grief for Charles in the fall of 1444.[6]

Louis the Dauphin, about to insult someone.
[1] From a poem by Charles of Orléans, a figure who will have a much more politically prominent role in this TL.
[2] For good measure, he was also actual Count of Provence and titular King of Aragon and Jerusalem, with further claims to Hungary and Cyprus.
[3] By 1435, Philip had started styling himself "Great Duke of the West."
[4] Radegonde OTL would die in the spring of 1445, having contracted pleurisy after a pilgrimage to Basilique Notre-Dame de l'Épine. As this is after our to-be-revealed POD, she will have a different fate.
[5] An alternate story has Stüssi brandishing his broad battle-axe and shouting, "Halt, citizens, halt!" To this a man of Zurich cried, "May God's lightning blast thee! All this evil comes from thee alone," and ran him through with his lance. The man had a point.
[6] A teaser for the POD that is to occur in the next update, which will be full of bloody battles and delectable deliberation!