Within the next few years greater attention will be given to a period of Roman Imperial coinage which, apart from special and isolated studies, has so far lacked a broad and balanced treatment. The completion, now near, of volumes VI, VII and VIII of ‘Mattingly-Sydenham’ will fill the large and difficult gap between the end of the third century and Pearce's volume IX, i.e. from c. 294 to 364. For the earlier Empire the great sequence of British Museum catalogues has furnished a powerful instrument by which imperial achievement can in some degree be measured against imperial claims or aspirations; and it is now reasonable to assert that a valid distinction is to be made between the imperial image as the emperors presented it and that which the ancient historians wished or chose to reflect. In the third century, and especially in the middle of the third century, the imperial coinage suffered an increasing debasement, not only in actual metal but also in types used with such indiscriminate generality that they must have diluted the previously selective imperial image to an ultimately negligible significance. Hence the interest of the coinage from c. 294 to 364. Avoiding altogether the excessive type-variation of the mid-third century, this seems often to wear a stereotyped or even rigid air; but in fact this economy of usage will allow a much more perceptive interpretation of those lesser variations which were from time to time permitted or necessitated. Such interpretation, against the general historical context of the time, should be a major exercise in the coming years.