Abstract
According to ‘Altars steeped in human blood’, the Posidonian tradition presents a coherent picture of the ritual and religious world of the Celts, where the Druids were wise philosophers, revered for their justice; keepers of natural and celestial knowledge; and intermediaries between the gods and humankind. Posidonius gives an insight into barbarian religious behaviour just before Romanization caused irreparable change. Caesar's emotive account emphasizes the near-absolute power that the Druids wielded in society; their control over religion and sacrifice; their role as teachers and their ability to exercise authority across tribal boundaries. In the 1st century ad, the Roman authorities made sustained efforts to break the power of the Druids.
