In Chaldaea the work undertaken by Nabopolassar and his dynasty was far more arduous. He had to rebuild nearly all the civil and religious buildings from their foundations, to undertake, as we know from more than one text, a general reconstruction.[154] A new Babylon was reared from the ground. Little of her former monuments remained but their foundations and materials. Temples richer than the first rose upon the lofty mounds, and, for the sake of speed, were often built of the old bricks, upon which appeared the names of forgotten kings. Nothing was neglected, no expense was spared by which the solidity of the new buildings could be increased, and yet, five or six centuries afterwards, nothing was left but ruins. Herodotus seems to have seen the great temple of Bel while it was still practically intact, but Diodorus speaks of it as an edifice "which time had caused to fall,"[155] and he adds that "writers are not in accord in what they say about this temple, so that it is impossible for us to make sure what its real dimensions were." It would seem, therefore, that the upper stories had fallen long before the age of Augustus. Even Ctesias, perhaps, who is Diodorus's constant guide in all that he writes on the subject of Chaldaea and Assyria, never saw the monument in its integrity. In any case, the building was a complete ruin in the time of Strabo. "The tomb of Belus," says that accurate and well-informed geographer, "is now destroyed."[156] Strabo, like Diodorus, attributes the destruction of these buildings partly to time, partly to the avenging violence of the Persians, who, irritated by the never-ending revolts of Babylon, ruined the proudest and most famous of her temples as a punishment. That the sanctuary was pillaged by the Persians under Xerxes, as Strabo affirms, is probable enough, but we have some difficulty in believing that they troubled themselves to destroy the building itself.[157] The effort would have been too great, and, in view of the slow but sure action of the elements upon its substance, it would have been labour thrown away. The destruction of an Egyptian monument required a desperate and long continued attack, it had to be deliberately murdered, if we may use such a phrase, but the buildings of Mesopotamia, with their thin cuirasses of burnt brick and their soft bodies, required the care of an architect to keep them standing, we might say of a doctor to keep them alive, to watch over them day by day, and to stop every wound through which the weather could reach their vulnerable parts. Abandoned to themselves they would soon have died, and died natural deaths.