William of Marseille was a thirteenth century English academic, teaching in France. He is known for the medical-astrological treatise De urina non visa.On Unseen Urine. Dated to 1219.. The method is to apply a horoscope to deduce properties of the urine of a patient, when that cannor be obtained; and then to proceed to diagnosis.The medieval doctor would be expected to make a diagnosis from the patient's urine. There is an obvious problem if the patient's urine can not be obtained. William solves this tricky question by casting the patient's horoscope and working out what the urine should have looked like. This book was still used at the University of Bologna in 1405. .