Una bevanda di apostasia: il comos mongolico nell’Itinerarium di frate Guglielmo di Rubrouck

The Franciscan monk William of Rubrouk narrates, meticulously and in great detail, his long voyage between 1253 and 1255 in central Asia, which took him all the way to Karakorum at the court of Mongke-Kahn. When describing Mongolian dietary habits, if on the one hand, Brother William records the centrality of koumiss (fermented mare’s milk), on the other, he describes the drinking of said beverage as comparable, by Byzantine Christians in central Asia, to an act of automatic abjuration of Christianity: a veritable apostasy that required a solemn and formal readmission into the Christian community. This article aims to focus on the unique dietary information contained in the Itinerarium by Brother William of Rubrouck, attempting to clarify what caused such a strong religious connotation to solidify around koumiss, to the point of making it an identity-creating line of demarcation.