The three principles to know, to know how and to know how to be are already condensed in the works of Theophilos (7th-9th centuries). Theophilus' De urinis was included in Latin translation in the Articella, probably because of its intermediate position between the texts of high doctrinal value by Hippocrates and Galen (lacking, however, a unifying 'theory of urine') and the epitomes, short manuals without any theoretical background. It thus forms an excellent synthesis of a cultural approach reconciling iatrosophia and techne and offers to the reader a text reconciling the theory and the practice, useful to health workers in hospitals, novice beginners and medical scholars. Thanks to his strong attention to the correlation between symptoms and pathology and to his search for assessment scales, Theophilus became the author on whom the birth of medical medieval studies was founded.