letters and despatches which were delivered by royal messengers. Though no royal letters have been found inscribed with the regular epistolary formulæ, a few tablets of the period contain what are obviously directions from the king. It was probably due to his encouragement of official and commercial intercourse between the scattered cities over which he ruled, that Shar-Gani-sharri was enabled to establish an efficient control over an empire which was more extensive than that of any earlier ruler. A study of the names upon the Obelisk of Manishtusu makes it clear that, already under the kings of Kish, the barriers which had previously surrounded and isolated each city-state had begun to disappear under the influence of a central administration. This process was accelerated in Shar-Gani-sharri's reign, and, although under the kings of Ur and Isin a conservative reaction appears to have set in, the great cities never returned to their former state of isolation even in the south. Another factor, which may have contributed to this process of centralization, may probably be traced in Manishtusu's text itself, and echoes of it may perhaps be detected in some of the later traditions of Sargon's reign. It will be remembered that the obelisk records the purchase by the king of some large landed estates in the neighbourhood of Kish and three other cities in Northern Babylonia, on which he intended to settle certain citizens of Akkad and their adherents.[61] This wholesale transference of a large section of the population of a city may well have been dictated by political motives, and it is possible that it was part of a general system, inaugurated by the kings of Kish with the object of substituting national feeling in place of the local patriotism of the city-state. According to this theory, Manishtusu's object would have been to weaken Akkad by the deportation of many of her principal citizens to the neighbourhood of Kish.