In the early part of this century it was still possible for a great Byzantine art-historian and archaeologist to write of his subject that in its fidelity to sacrosanct tradition Byzantine art is not without analogy to that of ancient Egypt. It had infinite decorative charm, but it grew languid for want of living ideas; it too readily abandoned initiative to live content in ‘the narrow proficiency of perpetual iteration’. The general trend of this century’s studies has been to demonstrate that …