S as a Graphic Form

The Latin S's sound history, descended from a Phoenician sign for a sharp sibilant by way of Greek sigma, is covered elsewhere in this atlas. Graphically, classical Athenian Greek wrote sigma as an angular zigzag in its monumental capital form, close to a stretched-out Z, though a rounder lunate form, resembling a C, was also common in later Greek and Byzantine writing.

The Etruscan and Roman letter descended from the angular tradition but rounded its strokes over centuries of cursive handwriting, producing by the classical Roman period the smooth double-curve S still used today; the shift from angular to curved is one of the more visually dramatic transformations any Latin letter underwent on its way from a Greek monumental inscription to a Roman one. The lowercase s is essentially the same double curve at a smaller scale, one of the few Latin letters whose upper and lower case remain almost identical in outline. S has no Roman numeral value of its own, though the abbreviation for the old British currency unit shilling, and the dollar sign some scholars trace to a crossed S derived from the Spanish peso mark, are later, unrelated uses of the letter's shape rather than part of the alphabet's own numeral or gematria history.