ABSTRACT
The financial system of the later Roman empire was the product of a long historical evolution and had as a result a complicated structure. Under the early principate, the chief financial minister was the a rationibus, who controlled the currency, the mines and the mints and the taxes, and handled the main items of expenditure. Beside him stood the procurator patrimonii who managed the property of the emperor, whose revenue was largely spent on public purposes. The patrimony came to be regarded as crown property and no longer the personal estate of the emperor, and Septimius Severus founded a new department, the res privata, to control the latter, which he rapidly built up by extensive confiscations. Later the patrimony was merged in the resprivata and the magister rei privatae became almost as important as the rationalis rei summae as the a rationibus was now called. Finally in the great inflation of the third century the yield of the old money taxes sank to a negligible sum and the office of rationalis declined in importance. The state came to rely on requisitions in kind to meet its principal needs, and to pay the army and the civil service largely in kind, food, uniforms, horses and arms. These requisitions and payments were made by the praetorian prefects, as quartermasters general of the army, acting through the provincial governors. The praetorian prefecture by the end of the third century became de facto the most important financial ministry. In the fourth century the resulting triple division had some rational justification. The res privata handled the rents from the state property and from them supplied the needs of the imperial household and money for imperial benefactions. The res summa or, as it was called from Constantine’s time, the sacrae largitiones, managed the currency and the revenue and expenditure in money. The praetorian prefecture handled revenue and expenditure in kind. From the end of the fourth century the requisitions and payments in kind were gradually commuted into gold and the special role of the praetorian prefecture disappeared. But the structure of the financial departments was now ossified and the prefecture continued to handle the bulk of the revenue and expenditure.
