Comparing these data we reach the conclusion that inhumation was abandoned, with a few exceptions, towards the end of the fifth century of Rome, to be resumed only towards the middle of the second century after Christ, under the influence of Eastern doctrines and customs. For the student of Roman archæology these facts have not merely a speculative interest; a knowledge of them is necessary for the chronological classification of the material found in cemeteries and represented so abundantly in public and private collections. The acceptance of cremation as a national, exclusive system brought as a consequence the institution of the _ustrina_, the sacred enclosures in which pyres were built to convert the corpses into ashes. Several specimens of _ustrina_ have been found near the city, and one of them is still to be seen in good preservation. It is built in the shape of a military camp, on the right of the Appian Way, five and a half miles from the gate. When Fabretti first saw it in 1699, it was intact, save a breach or gap on the north side. He describes it as a rectangle three hundred and forty feet long, and two hundred feet wide, enclosed by a wall thirteen feet high. Its masonry is irregular both in the shape and size of the blocks of stone, and may well be assigned to the fifth century of Rome, when the necessity for popular _ustrina_ was first felt. When Nibby and Gell visited the spot in 1822 they found that the noble owner of the farm had just destroyed the western side and a portion of the eastern, to build with their materials a _maceria_, or dry wall.