At the end of the second century ah al-Shāfiʿī (d. 204/820) advocated stoning as the sole penalty for adultery instead of an earlier rule that combined flogging with stoning. Al-Shāfiʿī's innovative doctrine was barely noticed by the jurisprudents, exegetes and ḥadīth collectors during the first half of the third century ah, but apparently provoked a legal debate shortly thereafter. This article explores the development of the third-century dual- vs. single-penalty dispute and its implications for the chronology of al-Shāfiʿī's Risāla.