Trying to bolster their claim to the French throne by adding more territory, the English broke the Treaty of Troyes. They invaded central France and, on October 12, 1428, began the siege of Orleans, only eighty miles south of Paris.
France had already lost control of its territory north of the Loire (in northern France). The English occupied this area thanks to the help of the Burgundians (French people who had a separate state within France). This link takes you to a map of Burgundy and France at the time of Joan of Arc.
Philip of Burgundy favored an alliance with England, not France. Charles, the dauphin, knew he could not count on the Burgundians to keep France for the French. Neither could the dauphin count on the French people themselves who had barely resisted English advances and who believed the English were invincible. These medieval pictures, from Froissart's chronicles and located at the BNF in Paris, depict the battle and the negotiations between France and England at Amiens. The town was ultimately lost to the English. By the spring of 1429, the situation looked hopeless for Charles and his countrymen.