In the 6th-7th centuries AD, treatises on uroscopy were written by Theophilus, Magnus and the author of work transmitted through the ms. Parisinus gr. 2260, Stephanus of Athens. These works are the first to deal comprehensively with the problem of urines, uroscopy and their clinical role, so that a philological and content analysis and examination of their reciprocal relationships may clarify an important period in the birth and development of Byzantine uroscopy, which represents a significant epistemological passage in the medieval history of medicine (e.g. the positing of relationships between physical signs and systemic diseases).