When, in co-operation with Sir Frederick Pollock, I was at work upon certain chapters in a History of English Law, and, in particular, a chapter on marriage, I found that, on pain of leaving the book shamefully incomplete, I was compelled to make an incursion into a region that was unfamiliar to me, namely, that of ecclesiastical jurisprudence. After some study, which must not be called prolonged or profound, but none the less was unprejudiced, I discovered that I was slowly coming to results which, though they have not wanted for advocates, have not been generally accepted in this country by those whose opinions are the weightiest, and have recently been rejected by the report of a Royal Commission signed by twenty-three illustrious names. To be brief, I found myself attributing to the Roman Canon Law an authority over the doings of the English Ecclesiastical Courts such as it is not commonly supposed to have wielded. In the first three of the following essays (the other three deal with some minor but cognate matters) I endeavoured to state the reasons that had convinced me.