The major fortresses of the Iberian peninsular controlled the most important routes in and out of the country. Although all these fortifications had existed prior to the French invasion, they were considerably renovated and updated according to the principles of French military engineering laid down by the great engineer Vauban. This renovation included the adding of ravelins, bastions, curtains, counterscarps and all the other defensive features of the period. This title examines these fortifications, their design, development and strategic importance. It also deals with the various attempts, both successful and otherwise, that were made to besiege and storm them, some of the bloodiest and most savage encounters of the Peninsular War.