Order and harmony may be preserved, even where an edifice is carried on by successive ages, each of which imparts to its work the stamp of its own developing skill and imagination. Very few of the great cathedrals were begun and completed in one style. Most of the great French churches show traces of the earlier Norman or Romanesque; most of the English Gothic, traces of the Norman or of the different periods of English Gothic architecture; but one dominating scheme has been followed by the consecutive architects. The lack of such a governing and restraining principle is felt in the exterior of Toledo. Further than this, although successive wars and religious fanaticism have with their destructive fury injured so many of the beautiful statues and exquisite carvings and much of the stained glass of the French and English religious establishments, still the architecture itself has in the main been left undisturbed. In Toledo, there is hardly a portion of the early structure and decoration of the lower, visible part of the Cathedral which has not been altered or torn down by the various architects of the last three centuries. As an obvious result, the portions of the exterior which are interesting are individual features, and not a unified scheme; and they are interesting historically, rather than in relation to or in dependence upon one another. The west front, which is the principal façade, the various doorways and completed tower form the most interesting portions of the exterior. The west front is flanked by two projecting towers, dissimilar in design. To the south is the uncompleted one, containing the Mozarabic chapel,[11] roofed by an octagonal cupola and surmounted by a lantern, strangely betraying in exterior form its Byzantine ancestry. [Illustration: Photo by J. Lacoste, Madrid CATHEDRAL OF TOLEDO The choir stalls]