Let us then, with open minds, turn to this art of the builder, "the strongest, proudest, most orderly, most enduring of the arts of men that if once well done will stand more strongly than the unbalanced rocks, more prevalently than the crumbling hills; the art which is associated with all civic pride and sacred principle; with which men record their power, satisfy their enthusiasm, make sure their defense, define and make dear their habitation."[2] CHAPTER I What Is Gothic Architecture?[3] _Le temps Où tous nos monuments, et toutes nos croyances Portaient le manteau blanc de leur virginité Où sous la main de Christ, tout venait de renaître._ --ALFRED DE MUSSET. About the year 1000 a new spirit animated the art of the builder in France. That rebirth, to which has been given the name Romanesque, held sway for a hundred and fifty years, and had reached its apogee when, in mid-XII century, it was superseded by the architecture we call Gothic. Gothic architecture did not spring up like a mushroom. Like all manifestations of art, it was the logical fulfillment of its predecessor. Romanesque and Gothic were phases of the same art. The dethronement of Romanesque was a voluntary abdication in favor of younger, more efficient leadership: "What is called the birth of Gothic is but the coming of age of Romanesque." The XI-century monks who built monastic churches cleared the path for the laymen builders of the Gothic cathedrals. With persistency, with courage, the monk architects went forward, seeking a way. And the way sought, the problem on which they concentrated their energies, was how to protect their churches by masonry vaulting without sacrificing amplitude or lighting.[4] Out of their trials to solve that problem there emerged a new principle of construction, and Gothic architecture was then born. Thrust and counterthrust was the law of its being. Instead of the Romanesque idea of equilibrium by dead load, by sheer mass, which may be called a continuous counterbutting of the vault's thrust, there now was substituted equilibrium by intermittent abutment. By means of diagonal-crossing ribs the vertical and lateral thrusts of the stone roof were collected at fixed points, which points alone had to be counterbutted. Thick walls were a necessity in a Romanesque edifice, if it were to be stable, but in a Gothic building the walls could be made a mere shell, since all the work was done by an active skeleton, a bone structure of stone, consisting of piers, arches, and buttresses. To define shortly, Gothic architecture is the art of erecting buildings with vaults whose ribs intersect (concentration of load) and whose thrusts are stopped by buttresses (the grounding of the thrusts). The never-ceasing downward and outward thrust of the vaulting is met by an equivalent resistance in pier and buttress and solid earth. Equilibrium results from that well-adjusted opposition of forces.