Byzantium! A name that glitters. A synonym for formality, unbending etiquette, luxury, exoticism. A word that stands for unyielding resistance to change, for codified, inflexible forms, for intrigue and bloodthirsty scheming. Say “Byzantium” and you stand before processions of saints and martyrs trapped in shimmering fields of gold and glass tesserae. You conjure up rigid figures who glare fiercely from the confines of icons and manuscripts, their gorgeously colored robes heavy with embroidery and punctuated by overscaled jewels, their gestures ritualized, exaggerated, theatrical. You see Yeats’s “sages standing in God’s holy fire/ as in the gold mosaic of a wall,” their solemn progress and otherworldly setting alike echoed by the thudding reiterations of “gold” and “golden” in the stunning last stanza of “Sailing to Byzantium.”

The reality of what that mag ...