Individual legionary soldiers were paid 225 denarii a year (calculated from the ‘‘ten asses a day’’ of Tac. Ann. 1.17) from the reign of Augustus to Domitian. In 83 ce the latter increased this to 300 denarii (Suet. Dom. 7.3; Dio 67.3.5). The next pay rise came under Septimius Severus (Herodian 3.8.4; HA Sev. 12.2), although its magnitude is unclear. The evidence is set out by M. Alexander Speidel (1992: 88) and Alston (1994: 113-15), who argue for a one hundred percent rise (to 600 denarii) and 50 percent rise (to 450 denarii) respectively. Herodian states that Caracalla gave a 50 percent rise to the praetorians in 212 ce, and Dio implies that all the troops received this rise (Herod. 4.4.7; Dio 78.36.3-4). That would produce an annual legionary salary of 675 or 900 denarii, depending on the size of Septimius’ increase. This level was in turn doubled by Maximinus in 235 ce (Herod. 6.8.8).
The relationship of auxiliary pay to legionary pay has been the subject of recent debate. M. Alexander Speidel (1992, following an argument advanced by M. P. Speidel 1973) has interpreted a document from Vindonissa to suggest that basic annual pay for an ordinary auxiliary soldier was five-sixths of that of a legionary ranker. While this has met with wide acceptance, Alston (1994: 122) questioned and rejected Speidel’s interpretation and instead made the radical suggestion (advancing no positive evidence) that auxiliary pay may have been at the same basic rates as legionary pay. He argues that the Roman army was less status-differentiated than modern colonial armies; hence scholars’ assumption that it would differentiate in terms of pay is unjustified. One might object that while there is little explicit evidence of legionary-auxiliary differentiation in terms of service, the Roman army and Roman society in general were so hierarchical and differentiated that such uniformity is implausible. MacMullen (1984b) has advanced a rough formula for calculating the overall cost of army pay. Using this for an army of 28 legions paid at the post-Domitianic rate, with a comparable number of auxiliaries paid (very roughly) at five-sixths that rate, the total comes to just over 100 million denarii a year.
Other expenditure on the army included the praemia paid to veterans on retirement and donatives paid on imperial accessions and anniversaries. Veterans received
3.000 denarii per man (5,000 for praetorians) from the reign of Augustus and 5,000 per ordinary soldier under Caracalla (Dio 55.23.1; 77.24.1; the figure given for praetorians in the text is garbled). However, some veterans still received land to colonize in lieu of cash payments. There was little settlement of veterans on Italian land after Augustus (but see Tac. Ann. 13.31; 14.27), but overseas veteran colonies remained important to the reign of Hadrian, and veterans continued to receive land in frontier areas in later centuries (Mann 1983: 65-8).
On the death of Augustus (and hence the accession of Tiberius), each legionary received a donative of 300 sesterces (75 denarii), with 1,000 going to the praetorians and 500 to the urban cohorts in accordance with the deceased emperor’s final testament (Suet. Aug. 101.2). As noted earlier, Claudius gave the praetorians
15.000 sesterces (3,750 denarii) on his accession, and Josephus says that he promised donatives to the rest of the army too (AJ 19.247), though it is possible that noncitizen troops, mostly auxiliaries, were excluded, as they were from the donative offered by Gaius upon his accession in 37 ce (Dio 59.2.3). It seems probable that the legions were included in these gifts even though most subsequent references only specify praetorians, as in the case of the 5,000 denarii given by Marcus Aurelius upon his accession (HA Marc. 7.9; Dio 73.8.4). It is possible that the proportions in the will of Augustus became standard (Campbell 1984: 167-8). The exclusion of noncitizen troops from these donatives, at least initially, suggests that in some sense they reflected the special relationship between the emperor and the Roman people.
Smaller donatives were paid on imperial anniversaries, such as the 25 denarii given by Claudius to the praetorians on the anniversary of his accession (Dio 60.12.4), and the 250 given to them by Septimius on the tenth anniversary of his, a sum that may be explained by the fact that this was the sum that he had paid when strapped for cash at the time of his proclamation in 193 ce - resisting a demand from the troops for ten times that amount (Dio 76.1.1; Herod. 2.14.5; HA Sev. 7.6, cf. Dio 46.46).