In the 12th century text “Secret History of the Mongols,” commissioned by Genghis Khan, a scene is described in which a warrior hit in the neck by an arrow is brought back to camp by a fellow solider. Mongols often used poisoned arrows, so, it was customary to suck the blood from arrow wounds — in this case the second person supports the first while sucking and then spitting out his blood. This scene must have been startling enough to have been included in the History.