Graeco-Romanism is immeasurable. The terms in which it could be stated
have yet to be discovered. It is the whole length of the slope from Sta.
Sophia to the Victoria Memorial pushed upright to stand on a base of a
hundred years. We are on heights from which the mud-flats are invisible;
resting here, one can hardly believe that the flats ever were, or, at
any rate, that they will ever be again. Go to Ravenna, and you will see
the masterpieces of Christian art, the primitives of the slope: go to
the Tate Gallery or the Luxembourg, and you will see the end of that
slope--Christian art at its last gasp. These _memento mori_ are salutary
in an age of assurance when, looking at the pictures of Cézanne, we
feel, not inexcusably, that we are high above the mud and malaria.
Between Cézanne and another Tate Gallery, what lies in store for the
human spirit? Are we in the period of a new incubation? Or is the new
age born? Is it a new slope that we are on, or are we merely part of a
surprisingly vigorous premonitory flutter? These are queries to ponder.
Is Cézanne the beginning of a slope, a portent, or merely the crest of a
movement? The oracles are dumb. This alone seems to me sure: since the
Byzantine primitives set their mosaics at Ravenna no artist in Europe
has created forms of greater significance unless it be Cézanne.

With Sta. Sophia at Constantinople, and the sixth century churches and
mosaics at Ravenna, the Christian slope establishes itself in
Europe.[10] In the same century it took a downward twist at
Constantinople; but in one part of Europe or another the new inspiration
continued to manifest itself supremely for more than six hundred years.
There were ups and downs, of course, movements and reactions; in some
places art was almost always good, in others it was never first-rate;
but there was no universal, irreparable depreciation till Norman and
Romanesque architecture gave way to Gothic, till twelfth-century
sculpture became thirteenth-century figuration.