A Medieval Companion to Aristotle: John Krosbein\'s Paraphrase on \'Liber de causis\'

This paper analysis and publishes John Krosbein's (fl. 14th c.) commentary on the 'Book of Causes'. He commentend upon all the works of Aristotle, and judging by the number of manuscripts, he was read in numerous schools in the Holly Roman Empire (today Germany and Poland). How can one explain the success of Krosbein’s commentaries? His undertaking is characterised by a concise and very synthetic explication of the text, unlike the endeavours of Albert the Great and Thomas Aquinas which were far too detailed to function as brisk introductions to Aristotle’s works, the pseudepigraphal treatises ('Liber de causis', 'De proprietatibus elementorum') and the 'Elements of Theology'. Krosbein’s method for reducing the length of his commentary consists mainly in selecting passages which seem important to him; in the case of the 'Book of Causes' and the 'Elements of Theology', he comments chiefly on the theorems and rarely appeals to secondary propositions. Within the academic system Krosbein’s paraphrases played a very useful role. Suitable for propaedeutic instruction in philosophy, they familiarised students with texts and doctrines which could be further developed over the course of their studies at the university. These commentaries likely functioned as successful introductory volumes, similar to the Handbook of or Companion to of our time.