look to the pasta

"Now it is common knowledge that cowards and brave men are born in all places. However, nation surpasses nation in warfare, and climate exerts an enormous influence on the strength of minds and bodies. In this connexion let us not omit what has won the approval of the most learned men. They tell us that all peoples that are near the sun, being parched by great heat, are more intelligent but have less blood, and therefore lack steadiness and confidence to fight at close quarters, because those who are conscious of having less blood are afraid of wounds. On the other hand the peoples of the north, remote from the sun's heat, are less intelligent, but having a superabundance of blood are readiest for wars. Recruits should therefore be raised from the more temperate climes. The plenteousness of their blood supplies a contempt for wounds and death, and intelligence cannot be lacking either which preserves discipline in camp and is of no little assistance with counsel in battle."

-- Publius Flavius Vegetius Renatus, Epitoma Rei Militaris (late 4th or early 5th century C.E.)