The French masters, who have contended that the Ile-de-France is the cradle of Gothic architecture, have had lesser controversies among themselves as to which special portion of the royal domain led in the evolution. M. Woillez, a pioneer, considered the environs of Beauvais the favored spot; M. Saint-Paul looked to the districts between Normandy and Paris; M. Enlart sought the nucleus in Amiens diocese in Picardy; and M. Lefèvre-Pontalis chose the classic diocese of Soissons. The two latter masters have modified their views since studying Durham's vaults, and they may modify them further in regard to Lombardy's early use of diagonals. The controversy is not closed. The France of that day was more a feudal confederation than a united kingdom, and some of the king's vassals ruled territories larger than his own. If the feeling of nationality is created as much by great achievements in common, as by political boundaries and the ties of blood, if, as all now agree, the enthusiasm of the Crusades, those holy wars against a common foe, helped to weld the rival sections of France into one nation, surely that other enthusiasm of the day, those other _Gesta Dei_ per Francos, the building of the Gothic cathedrals, played an important part in forming the national soul. From end to end of France they were building when at the battle of Bouvines a French king united with the jealous barons, with clergy and with burgess and with villein in a common defense of their native land. King, clergy, lords, and people fought at Bouvines, and king, clergy, lords, and people built the big national churches. All the energies of the times went to their making, all the primitive strong purposes, all the newly stirred intellect of the schools. Science was as needed for them as inspiration, for without the long manual training of the guilds, the mystic glow had not sufficed. There has crept into various architectural manuals, since first M. Viollet-le-Duc voiced it, a theory which scarcely needs refuting, so disproved is it by modern research.[13] Gothic art is considered as the layman's expression of revolt against the Romanesque art of the monks, an idea that denies the structural sequence of the two phases of the same art, and would present Gothic as a reaction against its predecessor, instead of its supreme development.