domes, a
peculiarity which is as distinctive of Byzantine (_i.e._, Eastern
early Christian), as the vaulted roof is of Romanesque (or Western
early Christian) architecture. Artists from Constantinople itself
probably visited France, and from this centre a not inconsiderable
influence extended itself in various directions, and led to the use of
many Byzantine features both of design and ornament.

As features in the exterior of their buildings, the roofs have been
in every period valued by the French architects; they are almost
always steep, striking, and ornamented. All appropriate modes of
giving prominence and adding ornament to a roof have been very fully
developed in French Gothic architecture, and the roofs of semicircular
and circular apses, staircase towers, &c., may be almost looked upon
as typical.[23]

_Openings._

The treatment of openings gives occasion for one of the most strongly
marked points of contrast between French and English Gothic
architecture. With us the great windows are unquestionably the
prominent features, but with the French the doors are most elaborated.
This result is reached not so much by any lowering of the quality of
the treatment bestowed upon the windows, but by the greatly increased
importance given to doorways.

The great portals of Notre Dame at Paris (Fig. 33), Rheims, or Amiens
(Fig. 35), and the grand porches of Chartres may be named as the
finest examples, and are probably the most magnificent single features
which Gothic Art produced in any age or any country; but in its degree
the western portal of every great church is usually an object upon
which the best resources of the architect have been freely lavished.
The wall is built very thick so that enormous jambs, carrying a vast
moulded arch, can be employed. The head of the door is filled with
sculpture, which is also lavishly used in the sides and arch, and over
the whole rises an ornamental gable, frequently profusely adorned with
tracery and sculpture, its sides being richly decorated by crockets
or similar ornaments, and crowned by a sculptured terminal or finial.

The windows in the earliest periods are simpler than in our E. E., as
well as of less slender proportions. In the second and third periods
they are full of rich tracery, and are made lofty and wide to receive
the magnificent stained glass with which it was intended to fill them,
and which many churches retain. Circular windows, sometimes called
wheel-