Shortly after the First Crusade toPalestine, Benedictine monks in different monastichouses in England and northern France turned towardsphysiology to contrast their foes with their ownarmies. They speak of courageous French fighters andweak-blooded, cowardly, cunning Saracens, both ofwhom are shaped by their regional environment andclimate. Guibert of Nogent (c. 1060–c.1125) and William of Malmesbury each directlyengaged ancient Hippocratic environmental theorythat took a geographic deterministic view ofpeoples’ physical and mental character, strength,intelligence and industry. Echoing these ideas,Orderic Vitalis (1075–c. 1142) and Baldric of Bourgueil(c. 1050–1130)commented on Turkish military cunning, a trait thatenvironmental theory accounted for on the basis of alack of blood. Environmental (or climate) theorypresented an explanatory structure for theclassification of essentialized mental and physicalqualities based upon topography, which Aristotle hadexpanded in his Politics to clarify groups’ status in ahierarchy of power. Aristotle’s work, which wasunknown in Arabic and was translated into Latin byWilliam of Moerbeke in c. 1260, introduced the concept ofnatural slavery, building upon environmental theory,arguing that the physiognomy and mental traits oflarge-bodied workers lacking rational qualitiesrendered them natural slaves. Various climatesfavoured different political systems, the weakersoutherners and irrational northerners being lesswell equipped for self-rule because they lacked asufficient capacity for reason. In line with ancientGreek stoicism, environmental theory accordinglyheld that only the most temperate region, where heatand coldness, moisture and dryness balanced out,nurtured the ideal, rational and brave man, able todefend his territory. Even before Aristotle’sPolitics wastranslated, however, climate theory was knownthrough texts produced in the military and monasticspheres.

This chapter is about how the adoption and adaptationof environmental theory fostered a biological modeof thinking about ethnicity, whereby thesignificance of the salubriousness and sacredness ofdomesticated spaces on occasion was identified withthe translation of power, learning and militaryqualities. Following a short explanation of whatenvironmental theory and its sibling humoral theoryentail, and their dissemination, this chapter willexplore how monks and schoolmen copied, adapted andapplied these ideas between 1100 and 1250.