The city of Orleans was at an important place on the river Loire. The English controlled large parts of France when they started the siege, and Orleans was the last thing stopping them from attacking the rest of France. There was not much south of the river to defend the people who served Charles VII of France, so the English came close to joining their northern lands in France with the land they controlled at Aquitaine.
The siege started on October 12, 1428 and its only major action until Joan of Arc arrived was the Battle of the Herrings. She initiated several attacks that ended the siege on May 8, 1429 - nine days after her arrival.
