Here is an example of the critical mindset required when dealing with place names mentioned in accounts of medieval military events.
In France at that time, and in fact almost everywhere, there were variations, sometimes dozens of them, in the spelling of place names and personal names alike (which can make historical research in contemporary sources a nightmare). This book, a 2022 modern edition and translation into modern French of the famous chronicles of the Hundred Years' War (XVth century) by Jean Juvenal des Ursins, prepared by the distinguished medievalist Joël Blanchard, mentions a brief military event. It serves as a perfect example of why one must always be cautious and cross-reference with other sources.
In 1420, the following is recorded in his book: "On the borders of the Île-de-France, the English laid siege to Montolivet. Upon learning this, the Lord of Offemont gathered troops and attacked the besiegers; English soldiers were killed and taken prisoner, and the siege was lifted."
Montolivet is located east of Paris, near Coulommiers.
Now, here is the original version of the chronicle I have on hand: "The English laid siege to Montpillouet, near the French border; the Lord of Auffemont learned of this, gathered a force, and struck at the besiegers. In the end, many English were killed or captured, and the siege was lifted.."
So, according to the book, the place name spelled Montpillouet is actually Montolivet. In reality, however, that is not the case, for two reasons:
No other source, so far, mentions a siege at that location during that period. The second point is that other sources do indeed mention a similar event, an English siege hastily lifted thanks to the Lord of Offemont, such as the chronicles of Enguerrand de Monstrelet; however, this refers to the siege of Montépilloy, not Montolivet.
Located in the Valois region north of Paris, the site had been held since 1417 by an Armagnac garrison under Captain Robert d'Esnes. In 1420, it was besieged by a force of over 500 Anglo-Burgundians, who were driven off by an army led by three French lords; the engagement resulted in 60 deaths and the capture of Captain Louis de Pacy. Ironically, Montépilloy was likely not very well-known at the time; it only gained prominence "thanks to" the encounter in August 1429 between the Anglo-Burgundian and Franco-Scottish armies. The common spelling for the place name Montépilloy is mainly "Mont-Espilloy."