High Quality Content by WIKIPEDIA articles! The Oculus Sacerdotis was a 14th-century book by William of Pagula. Divided into three volumes written between 1320 and 1326, the book sought to be a comprehensive manual for parish priests, and covered the confessional, sacramental theology and preaching. Described as "deep, all-encompassing and quite encyclopaedic", sections of the book were in use up to the late Middle Ages, and approximately fifty copies are known still to exist in various libraries.