One of the tenets of this religion was a belief in the immortality of the soul, and also in its transmigration. As to the nature of their gods we know little or nothing, except that to them were offered human sacrifices, who were sometimes criminals and at other times prisoners of war. Of temples they appear to have had few, but to have performed their mystic rites in the secluded groves of oak which were then found on every side. The Druids were exempt from military service, and were at once priests, lawgivers, and teachers. From the time the Romans penetrated into Northumbria (see p. 15) near the beginning of the fifth century, the religion of the people of that district (which includes, of course, Lancashire) must have undergone a gradual change, as the polytheism of the Romans made itself apparent. At all their large stations the conquerors erected temples dedicated to their gods, and altars to their various deities were put up in every direction, and thus, no doubt, year by year the influence of the Druidical priesthood diminished, and was probably finally extinguished by the more attractive worship which found favour in imperial Rome. After the Romans vacated Lancashire, the conversion of Constantine the Great to Christianity (see p. 17) had no doubt some effect upon religious thought even in Northumbria. But long after the Roman Empire became a Christian State, the tribes which were then struggling for supremacy in Britain still adhered to the old pagan worship, and _Thor_, the god of thunder, _Wodin_, the god of war, _Eostre_, the goddess of spring, and a host of others, were numbered amongst their deities. They believed, however, in a future state, as their warriors slain in battle were supposed to inhabit a bright and happy palace called _Valhalla_. Near the end of the sixth century, King Æthelbert, who ruled in Kent, married the daughter of King Charibert of Paris, and by the terms of her marriage contract she was to be allowed to enjoy the exercise of Christian worship, which she did in a small chapel near Canterbury. With her, from France, came a Frankish Bishop named Liuhard, who was soon followed by a Roman Abbot named Augustine, who came by instructions from Pope Gregory I., accompanied by some forty monks, who were to establish the Christian religion in Kent; they ultimately persuaded the King to be baptized, and this event may be regarded as the foundation of the Christian religion in England. Little by little the new religion spread, and in A.D. 627 Edwin, the King of Northumbria, became a convert through the instrumentality of his wife, who was a daughter of Æthelbert, (see p. 42), and Paulinus, one of the company who came to Britain with Augustine. He had been consecrated to the episcopate by Justus, Archbishop of Canterbury, "in order that he might be to Ethelburga, in her Northern home, what Liuhard had been to her mother in the still heathen Kent."[169] On the