This endurance of custom becomes the more remarkable when we remember that great changes have occurred in the mode of treating the corpse at burial. At first there was inhumation; then we have a period during which inhumation and cremation were, to some extent, contemporaneous, while, as a variant, partial burning of the body was common. Cremation gradually becomes obsolete, and earth-burial again comes into vogue. If we carry back our thoughts to the advent of Christianity into Britain, we see that the trend of custom was the exact reverse of that which obtains in our day, when cremation is very slowly replacing earth-burial. The substitution of inhumation for the funeral pyre is one of the four chief distinctions drawn by Mr Romilly Allen between the burial customs of the Celtic pagans and the Celtic Christians[676]. Yet the change was a slow one; in the remote fastnesses of the country, the custom of burning bodies lingered for generations, though it was generally extinct in the fourth century of our era[677]. Indeed, Macrobius, the critic and philosopher, who wrote at the beginning of the fifth century, declared that cremation had been discontinued for so long a time that it was only from books that he could glean information concerning the custom[678]. Whether the turnover from cremation to earth-burial were always the result of religious or of racial influences is a moot point[679]. The evidence seems to prove, as already hinted, that in Britain the cause was mainly religious (p. 263 _supra_), though one dare not assert that religion was the sole cause. Cremation must always have been a comparatively expensive process. Someone has well said, “To this day we speak of the ashes of the great, and the bones of the poor.” At all events, transitions may be noted, as in the case of the famous flat-earth burial-ground at Aylesford, which was referred to in the preceding chapter. The ashes of the “family circle” represented at Aylesford had been enclosed in urns, and then placed in pits, as before stated (p. 261 _supra_). Sir A. J. Evans supposes that the variation of custom was due to the influence of Belgic conquerors. The urn-burials represented at Aylesford superseded the old skeleton interments of the late-Celtic peoples, as exemplified in the “chariot-burials” of Yorkshire, where the skeleton of the departed warrior is laid alongside the chariot[680]. In Scandinavia and Northern Germany there was a further intermediate stage, for the ashes were sometimes deposited in the grave without any enclosing urn. To such graves the Northern archaeologists apply the term “Brandgruben,” or cremation pits. This mode of burial is connected with the La Tène period of culture[681].