This volume of essays honours Henry Chadwick, probably the greatest and best-known of English scholars of early Christianity. The essays, written by many of the leading theologians and church historians in the English-speaking world, discuss different aspects of how Christianity developed norms and standards in its teaching, how it came to have - and to enforce - a definition of orthodoxy and heresy. It is a collection of fundamental work by internationally recognised experts. It covers issues of orthodoxy from the first right up to the sixth century, and its wide-ranging surveys of centrally important material in early Christianity will find broad appeal among scholars and students of Old and New Testaments, medieval history and patristics.