Since English lawyers started writing text books about the law of evidence, they have denied that religious confession privilege exists at common law. However, that statement of the law surprises those who recognise confessional secrecy dating back into the first millennium AD. It is also counter-intuitive in Federal Australia since the one human freedom which the Constitution has guaranteed since 1901 is the “free exercise of any religion”. This thesis analyses the legal conclusion that there is no religious confession privilege at common law against available historical materials. Those materials include the origin of confessional secrecy in Christian practice and the entrenchment of that practice in canon law; the recognition and even the reception of canonical practices in the custom that became the common law; and all the English common law cases that have affirmed or denied religious confession privilege whether in passing or in an arguably precedential way. The reason why clear evidence of the existence of the privilege even seventy years after the English Reformation has been ignored by the text writers is traced to an uncorrected interpretive error made by the text writer Peake in 1801. His error has been uncritically followed and affirmed by later commentators and judges. However, until Gavan Duffy J decided Cook v Carroll in Ireland in 1945 and the Supreme Court of Canada decided R v Gruenke in 1991, there was no reported decision on religious confession privilege anywhere in the British Commonwealth. All else that had been written was at best obiter dicta. The factors that influenced those two courts to recognise not a narrow religious confession privilege but a more encompassing confidential religious communications privilege are then measured against Australian jurisprudence to suggest whether the High Court of Australia would come to a similar conclusion.