The political and administrative requirements of the Roman state during the early years of the Principate demanded an increase in the annual number of consulars. When Augustus finally acted to remedy this situation in 5 b.c., he introduced a system of suffect consuls and thereby increased the number of consuls from the two per annum of the Republic to four. A regular practice became established whereby one or both of the ordinary consuls retired at the end of June to be (...) replaced in office for theremainder of the year by a suffect consul. For the reigns of Gaius and Claudius additional suffects were included in many years and a new pattern can be seen to have emerged. It was usual now for each ordinarius to hold office for the first six months of the year except in some special cases where the ordinarii resigned at the end of two months and their place was taken by a pair of suffects who remained in office for the next four months to serve out the more regular tenure of the ordinary consuls. Under Nero, the innovation of this two-month ordinary consulship was not perpetuated and ordinarii usually remained in office for the full six months. Suffect consulships throughout the period a.d. 38–68 were held for periods of either two, four or six months. The Civil War of a.d. 68/69 and the consequent changes of emperor broke the above pattern. For 69, there are no fewer than sixteen consuls known to have held office during the year. Such confusion, however, would not be unexpected given the startling events of this year. Of considerable importance to students of the early Empire, therefore, is the question of what happened to the system of allocating consulships during a particular year when the state had once again settled itself down to running in routine under the victorious Flavian emperors. The answer to this question will be of particular importance for prosopographers of the early Empire for whom chronology is the backbone of their investigations, since the fasti for the reigns of Vespasian and Titus are notable for the number of years in which the complete list of consuls is lacking. (shrink)