In his Apology of the Church of England as well as many of his other works, John Jewel defended the orthodoxy of the Elizabethan Church on the basis of the following criteria: Scripture, the first four general councils, the writings of the Church Fathers, and the example of the primitive church.1 By emphasizing these authorities, the bishop of Salisbury also sought to impeach the Roman Church’s claim to orthodoxy by arguing that doctrines and practices which developed subsequently to the early (...) church as defined by these criteria contradict them, thereby nullifying its charge of heresy against Protestants while simultaneously indicting the papacy itself as heretical. A question that emerges from studying Jewel’s prodigious polemical works concerns the source of this means of determining orthodoxy. Answering this question requires a close analysis of the apologist’s use of sources. This article will attempt to answer this question by arguing that this criteria for defining orthodoxy derived mainly from canon law tradition that is confirmed specifically by Gratian’s Decretum. This thesis maintains that Jewel’s criteria constituted a form of the ius antiqua with which he attacked the ius novum that provided the authoritative basis for papal supremacy, and in so doing, sought to vindicate the Elizabethan Church’s place in ancient catholic tradition. (shrink)