Philo of Alexandria was an important apologist of Judaism, presenting it as a tradition of venerable antiquity that, far from being a barbarian cult of an oriental nomadic tribe, with its doctrine of monotheism had anticipated tenets of Hellenistic philosophy. Philo could draw on Jewish tradition to use customs which Greeks thought as primitive or exotic as the basis for metaphors: such as "circumcision of the heart" in the pursuit of virtue. Consequently, Hellenistic Judaism emphasized monotheistic doctrine ("heis theos"), and represented reason ("logos") and wisdom ("sophia") as emanations from God.