διάδημα

Diádēma comes from the Greek diadéō, meaning 'I bind around.' The original diadem was not a jeweled crown but a white ribbon or cloth band tied around the forehead. Persian kings wore such bands as markers of sovereignty. When Alexander the Great conquered the Persian Empire in 330 BCE, he adopted the practice, wrapping a white cloth strip around his royal Macedonian kausia hat. His Macedonian generals grumbled about the Persian affectation. They were watching the birth of a symbol.

Alexander's successors — the Diadochi, literally 'the successors' — fought brutal wars over who would inherit his empire. The word Diadochi comes from the same root as diadem. Each successor who claimed kingship adopted the white band. The Ptolemies in Egypt, the Seleucids in Syria, the Antigonids in Macedon — all wore the diadēma. A strip of cloth became the standard proof of Hellenistic royal legitimacy.

Roman emperors initially avoided the diadem because it smelled of monarchy, and Rome was officially a republic until it wasn't. Augustus wore a laurel wreath. Constantine, in the fourth century, was the first Roman emperor to wear a pearl-studded diadem openly. By then, the cloth strip had become a metal band set with gemstones. The symbol had hardened from textile to metal, and no one called it a bandage anymore.

English borrowed diadem through Old French diadème in the thirteenth century. By then it meant any ornamental headband or crown. The word retained a literary, slightly archaic register — 'crown' is common, 'diadem' is poetic. Alexander would have recognized neither the jeweled object nor the reverent tone. His was a strip of linen.