The English-held fortress at Orléans attacked by Joan of Arc in May 1429 was Les Tourelles.
Les Tourelles was a fortified bridgehead guarding the southern end of Orléans’s bridge over the Loire. Its position made it a crucial part of the English siege system. On 7 May 1429, French forces launched an assault on the fortress, and Joan was wounded during the fighting but returned to the attack.
The capture of Les Tourelles on 7 May helped make the English siege untenable. The remaining English positions were abandoned soon afterward, and the siege was lifted on 8 May. This is why accounts sometimes describe the assault on Les Tourelles as the decisive final action of the siege.
Les Tourelles should not be confused with the nearby English fortifications of Saint-Loup and Saint-Jean-le-Blanc, which fell earlier during the French offensive.