Introduction

As seen in the previous chapter, our knowledge of the tax-system of the Principate is very indistinct. Tax inscriptions are very few, and surviving legal sources, almost all selected at a much later date, throw very little light on taxation in this period. With the late Empire, the position changes. Legal texts bearing on taxation become relatively abundant, and a series of detailed census inscriptions survives, together with some relevant literary evidence.

This extreme imbalance between what is known at different dates greatly restricts comparisons. It seems obvious in itself that important features of the Diocletianic tax-system, if not explicitly encountered in earlier sources, should represent innovations. But there are almost no detailed general descriptions of what preceded it. Where evidence will allow, it is worth trying to assess how new Diocletian's system was. The present chapter examines the main Diocletianic land tax-unit, and its implications both for the tax-system, and for the level of agriculture manpower.

Our knowledge of land-taxation of course remains very imperfect even in the late Empire. It is limited both by the increasing insistence of imperial draftsmen on literary elegance at the expense of exactness (adding to the problems of terminology in literary sources of the Principate seen in the previous chapter), and by the fact that isolated fragments of information are spread over a long period. Though the constitutions are dated, they are generally too few to allow effective inferences about long-term change.