The arabesque is easiest to define by what it refuses. It is drawn from the plant world, stem, leaf, tendril and blossom, yet it refuses botany: no species can be named, no root or ground supports the stem, and growth obeys rhythm rather than gravity. A stem forks at a regular interval; each fork carries a stylised leaf or palmette; the leaf itself may sprout a new stem and fork again; and the scroll runs on, capable of endless extension and of being cut by its frame at any point without loss.
Ernst Kuhnel, whose short study remains the classic account, traced how this system crystallised. Late antique art had bequeathed the Mediterranean a naturalistic repertoire of vine and acanthus scrolls. In the hands of craftsmen working for the early Islamic courts, above all in the ninth-century stucco of Samarra, the plant forms were progressively abstracted: the leaf flattened, split and rejoined, the stem became a pure line of movement, and the last memory of a growing plant gave way to an ornament governed by symmetry, reciprocity of figure and ground, and beat. By the tenth century the arabesque existed as a system with its own logic, and it spread wherever Islamic art reached, from Cordoba to Samarkand, worked in stucco, stone, wood, metal, ceramic and the margins of manuscripts. Europe met it through trade and named it arabesco, work in the Arab manner; the craftsmen of the Persian world called the mode islimi.