"I have described the contraceptive means known to different eras, and what can be inferred as to their diffusion and employment. The data here set forth, gathered from the canon law, the manuals for confessors, the commentaries of theologians and canonists, and medieval medical books and herbals, substantially alter the picture formerly drawn of contraceptive practice. In particular, the period between 400 and 1600 will be seen to be marked by a possession and use of contraceptive means which previous accounts have not suggested. It was in the face of this contraceptive practice that the doctrine upon it was promulgated in western Europe."