Wow! I climbed to the Boulards gardens, which overlooking the city: here we can see vestiges of the surrounding wall, but also the arches of the old hospital (12th - 13th centuries). In the Middle Ages, Gien was entirely fortified. We counted 4 successive expansions. Those fortifications were raised in the 14th century.
In the 10th century, a castle with its walls already existed by a rocky spur overlooking the river Loire; down here, houses. The fortress and the little city were maybe already defended by a wall in the 11th century...
A second and a third wall protected the city from the 13th century to the 15th century. In the reign of king saint Louis, in 1246, they built a stony bridge (some parts of this old building are still in the inner masonry of the current bridge). From 1481 to 1522, in the reign of Anne of France (countess of Gien and Kingdom's regent), the surrounding wall was extended in order to protect the western part of the city.