Between the lands of Sumer and Akkad there was no natural division such as marks them off from the regions of Assyria and Mesopotamia in the north. While the north-eastern half of the country bore the name of Akkad, and the south-eastern portion at the head of the Persian Gulf was known as Sumer, the same alluvial plain stretches southward from one to the other without any change in its general character. Thus some difference of opinion has previously existed, as to the precise boundary which separated the two lands, and additional confusion has been introduced by the rather vague use of the name Akkad during the later Assyrian and Neo-Babylonian periods. Thus Ashur-bani-pal, when referring to the capture of Nanâ's statue by the Elamites, puts E-anna, the temple of Nanâ in Erech, among the temples of the land of Akkad, a statement which has led to the view that Akkad extended as far south as Erech.[15] But it has been pointed out that on similar evidence furnished by an Assyrian letter, it would be possible to regard Eridu, the most southern Sumerian city as in Akkad, not in Sumer.[16] The explanation is to be found in the fact that by the Assyrians, whose southern border marched with Akkad, the latter name was often used loosely for the whole of Babylonia. Such references should not therefore be employed for determining the original limits of the two countries, and it is necessary to rely only upon information supplied by texts of a period earlier than that in which the original distinction between the two names had become blurred.