During the crusades of the middle ages, these knights were well recognized with their distinctive white mantles emblazoned with a red cross. Though their original purpose was to protect pilgrims from danger eventual they became defenders of the Crusader states in the Holy Land and were known as brave and highly skilled warriors.
He lays his life on the line in the defense of his adopted world. Every action he takes, and every modification he makes to his formidable body, is done to protect Earth. Optimus is usually depicted as having rose up from the lowly worker to become a champion in gladiatorial combat.