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Augustan Reforms of the Senate

Throughout the Augustan period, there were several attempts to reform the senate.

The Restoration of the Republic

The first took place in 28 BC and was part of the Augustan attempt with Agrippa to restore Roman public institutions. It is explicitly framed as an attempt to reduce the number of senators, which had swelled during the civil wars to perhaps over a thousand. It seems that Caesar and the triumvirs had rewarded at least some of their followers with senatorial status.

Suetonius (Augustus 35) reports that the reform was unpopular and Octavian, as he was then, had a bodyguard of senators and took to wearing a breastplate during senatorial meetings. Nevertheless, Octavian seems to have removed only fifty from the senate through moral pressure; another 140 were expelled. One guesses that it was members of this group who were upset (Dio, 52.49).

The purge appears not to have been directed at removing opponents but at ensuring the high status of those who served in the senate. Nevertheless, very few individuals appear to have felt themselves to have been in the lesser category of senators.

The Purge of 18 BC

Reinforced by his success in 20-19 BC, Augustus returned to the issue of senatorial membership in 18 BC. This can be seen again as an attempt to restore the senatorial order to its Republican prestige. So anxious was Augustus to be seen to be politically impartial that he devised an extraordinary and complex system to fill the senate. The aim was to reduce the number of senators, perhaps to as few as 300 (Dio, 54.14-15).

The scheme involved the selection of a senatorial commission of 30. Each of those 30 was to choose five persons of the required standing. From each five, one was selected by lot. The thirty so chosen became the first appointed to the senate. Judgement of peers had been exercised and the gods consulted through the use of lot.

The process was then repeated by the 30 to select another 150, who would then be reduced to 30 by lot. This second thirty would select another 150, who would again be reduced to the third group of 30. This was to continue until 300 men had been appointed.

It takes very little imagination to understand that such a process could go very wrong very quickly.

Corruption was suspected. The random elements in the choosing and the working of the lot left distinguished figures off the list. Sons found themselves resigning in protest at their fathers being overlooked.

Eventually, Augustus took all the lists in an appointed 600 senators.

A Senatorial ‘Law’ of 18 BC

Dio mentions a law or a regulation on senatorial membership  (Dio, 54. 17). This is odd. Senatorial membership was governed by a censor. A censor would review the list of senators and remove any he felt were inappropriate. In the late Republic, it seems that the consuls likely supervised the drafting in of new senators. If there was a qualification for the senate, it was likely being elected to a junior magisterial position.

We know little about the content of the law/regulation other than it set  a minimum census requirement for senatorial admission at 400,000 sesterces. 

It is possible that Dio makes a mistake here since it seems likely that the equestrian census requirement was already at 400,000 sesterces from c. 141 BC. But there may have been no formal requirement, before Augustus, for senators to be drawn from the equestrian order, but there was clearly such an expectation from the early first century BC. It is also possible that there were a small number of poorer senators, perhaps even from distinguished families, who could not make the census requirement.

The census level was set at a 1,000,000 by 13 BC. We have two possible options.

  1. Augustus first established a rule that senators must meet the equestrian census requirement to be eligible and then quickly emended that position to create a senatorial census level of 1,000,000.
  2. Dio got confused and there was one legislative act in 18 BC that set the senatorial level at 1,000,000.

Augustus appears to have allowed, perhaps by this same law, sons of senators, to wear the senatorial toga (it had a broad purple stripe). Those boys were also encouraged to listen to senatorial debates. The changes in regulation worked to make the senatorial class more exclusive and to encourage that sons would follow fathers into the senate.


Filling the Senate: 13 BC

Five years later, in 13 BC, Augustus returned to the issue of senatorial membership again (Dio, 54.26). The senatorial level had been raised to 1,000,000 sesterces. One might expect it to produce an annual income of 40,000 – 60,000 sesterces. This was a substantial amount of money for a family, the equivalent to the annual income of 50 – 60 soldiers. In terms of imperial wealth, however, it was nothing. The raised census level caused problems for some senatorial families. Younger members of established senatorial families refused to serve in the senate, claiming that they did not meet the financial requirements. The senators actively sought to widen the pool of recruits by bringing formerly equestrian families into the senate. Augustus himself looked into the matter to try and secure the required number of senators.

Within the space of five years, Augustus had gone from trying to weed out unsuitable senators to searching for new recruits.

Reforming the Senate Again: 11 BC

The reform of  11 BC (Dio, 54.35) is briefly attested. A quorum of 400 was set for any senatorial decree to have validity. That’s probably quite a high proportion of the senators. Although there had been attempts to reduce the number of senators and we can see that the figure reduced from more than 1000 to 600, if the senate was receiving 20 new junior members every year, we’d expect total membership to be 400-600 (allowing for deaths, etc.). There would also be a number of senators away in the provinces at any one time.

Augustus again seems to have looked at membership, concentrating on those under 35 and looking at men who had not followed their fathers into the senate. It suggests that once more he was worried about low senatorial membership.

Sponsoring the Senate: AD 4

Augustus held a reduced census in AD 4 (Dio, 55.13). He again investigated senatorial membership. This time he decided to give money to the children of senators who could not make the census requirement. Some were made up to the census level, but in the case of 80 individuals, their wealth was increased to 1,200,000 sesterces. If we imagine that the senators numbered 450 – 600, then 80 or more individuals being directly sponsored by Augustus was a substantial proportion of the senators.

Once more it seems as if there was an issue with senatorial membership.

Augustus also reformed the senatorial career structure. None of these reforms suggest that Augustus was packing the senate with his own supporters.


Octavian in 28 BC                                    Senatorial Careers                    Reform and Order

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