When first published in 1958, The Canons of the Council of Sardica, AD 343 at once became the standard account of the canons passed by the Western bishops at Sardica in 343 and the thinking on church matters that lay behind them. In this new edition Hamilton Hess has updated his account in the light of recent literature, included new materials and the full texts of the canons, and translated all quotations into English to reach a wider audience. Three new opening chapters make a fresh contribution to the study of early church history in giving a comprehensive analysis of the rise of the conciliar movement from its earliest beginnings to the fourth century establishment of councils as exclusively episcopal legislative assemblies. It is also shown that the emergence of canon law was a gradual evolutionary process leading towards the sixth-century organization of canonical collections as juridical ecclesiastical codes parallel with and complementary to the contemporary civil codes of the Roman Empire.