John was a voluminous writer , but many of the works attributed to him are spurious. Among his most important writings are: ( a ) Breviloquium de sapientia sanctorum , a short discussion on Christian wisdom, immediately followed in a number of our printed texts by the Breviloquium de virtutibus antiquorum principum et philosophorum , which uses the lives of the great men of the ancient world to illustrate the four cardinal virtues; ( b ) Summa collationum ad omne genus hominum or Communiloquium , a long treatise in seven parts and abounding in illustrations that instruct the preacher on how to address all kinds of men; ( c ) Compendiloquium de vitis illustrium philosophorum et de dictis moralibus eorundem , a treatise in ten parts, intended to afford stimulating examples for Christians from the lives and sayings of ancient philosophers . Other works include: Summa de Paenitentia , Summa Iustitiae , Moniloquium (on vices and virtues and their rewards), Legiloquium (on the Ten Commandments), some sermons, and perhaps some commentaries. John is also said to have begun the popular Manipulus Florum or Flores Doctorum , which was finished by Thomas of Ireland . These manuals are mostly compilations. They reveal no depth or originality of thought and show no interest in metaphysics, mathematics, or natural science, but give proof of John 's wide reading and reflect the emphasis placed by him on practical teaching. He quotes from a wide range of Latin writers , classical, patristic, and medieval, including the works of Averroes , Avicenna , and others, but Greek authors and philosophers he knew through translations only. His favourite ‘modern’ is John of Salisbury . With rare exceptions, ‘ John of Wales ’ effaces himself almost completely; and the absence of an independent critical attitude towards his work leads him into many contradictions and absurdities. References to his own contemporary world are also rare. John 's compilations were deservedly popular for several centuries, both for their fund of apt exempla , their sound practical morality, and their spirit of tolerance.
Professor William Hopkin Davies, M.A., Aberystwyth
Published date: 1959