But one essential difference there was between them, and that is, that whereas in Mexico the teocallis seldom possessed interiors, this was very frequently the case with the temples of Babylonia. It is true that the Mexican temples had attached to them buildings called _teopan_, but these appear to have been dwelling-places for the various grades of priests. In Babylonia, on the other hand, another description of residence arose. This was the temple proper, apart from the zikkurat or tower. Most Babylonian cities had a definite religious quarter, and excavations have made us familiar to some extent with the plan and appearance of these. Perhaps the best known example is that at Nippur, the extent of which appears to have been about sixteen acres. A large court was lined with brick columns, and when excavated was found to have supported a wooden roof. Close to this was the building in which the temple records were kept. The people gathered for worship in a second court of sixty wooden columns with supports and capitals of metal, and there, in a basin specially built for the purpose, they made their ablutions before offering up sacrifice. At the eastern end of this courtyard was placed a tent containing the ark. This kind of courtyard may be said to be characteristic of the Semitic worship, as there was undoubtedly such a structure in most Hebrew temples. This court of columns was surrounded by chambers which probably served the purpose of administrative offices and perhaps dwellings for the priests and attendants, or booths for the sale of sacrificial offerings. The training college for the younger priests was also within the temple area, as were the astronomical observatories, and around these gathered the learned of the district, just as they did in the temple at Jerusalem to dispute concerning religious matters and to split theological hairs. The Babylonian priests were also the lawyers of their period, and the courts of justice were probably hard by the temple. Many of these religious areas, as, for example, those at Babylon, Nippur, Sippar, and Ur, must have been so extensive as to have constituted what were in reality sacred cities. The whole was enclosed by a containing wall, and even the several divisions of the temple buildings were also surrounded by lesser walls. The material of which these edifices were built was the universal one of brick. In early days sun-dried brick was employed, but as its use resulted in the crumbling and speedy destruction of most of the edifices composed of it, kiln-dried bricks were substituted for it, and as these were often glazed their durability was much enhanced. The cement used to hold these together was common bitumen, found in great quantities in Babylonia, and the roof was usually built of wood, cedars from Lebanon being a favourite material for carpentering.