Many of the towns were in their origin border outposts; and their massive towers, fortified churches, and thick walls, with the suburbs huddling close against them for protection, marked the enveloping atmosphere of danger. Since it had been difficult at first to attract the industrial classes to such surroundings, rulers of Castile had been driven to grant _fueros_ or charters, to the inhabitants embodying numerous privileges and a large measure of self-government. Then the time of danger passed; the Castilian boundary pushed farther south, and other fortified towns were needed to defend it; but the citizens of the old outposts clung jealously to the _fueros_ of their fathers and defied either royal or seignorial control. “Ce sont de veritables petits états,” says Mariéjol, speaking of the Castilian municipalities in mediæval days; but the description that implies peculiar powers shadows forth also peculiar difficulties. The city that would keep its independence would have to struggle continually against the encroachments both of the Crown and of neighbouring territorial lords. It must for this purpose maintain its own militia, and, most arduous of all, watch carefully lest it should fall into subjection to its very defenders. Not a few of the municipal councils came in time to be dominated by a class of “knights,” or nobles of secondary rank, whose quarrels and feuds endangered industry and filled the streets with bloodshed. The principal civic official was the “regidor”; but the Crown had by the early fifteenth century succeeded in introducing in many cases a representative, the “corregidor,” whose business it was to look after royal interests. His presence was naturally resented by the more influential citizens and, where he dealt corruptly with the people, disliked by all; but an honest corregidor, who was unconnected with local families and therefore without interest in the local feuds, and who had no axe of his own to grind, was a Godsent help to the poorer classes. Besides appointing corregidors, the Crown had also begun to influence the municipalities in another way, through a gradually increasing control of the “Cortes,” or national parliament of Castile. This body consisted of three “Estates”; the nobles, whether _ricos-hombres_ or _hidalgos_ of lesser grade; ecclesiastics; and the Third Estate, or “Commons.” On an occasion of outward or obvious importance, when a succession or a Council of Regency were under dispute, or if an oath of homage to a new sovereign or the confirmation of some unprecedented act were required; all three “Estates” would meet together at whatever town the King happened to be staying. Such was a “General Cortes.”