Summa de opiatis, a treatise on drugs attributed to Petrus Musandinus or Pedro de Musanda (12th century), known as the teacher of Aegidius Corboliensis or Pierre Gilles de Corbeil (1165-1223). Rubric (f. 18v) : 'De opiatis secundum magistrum petrum / demussadat', incipit: 'Omnis medicine opiate ...