What it was
The main direct taxes were on land and on persons, levied in the provinces. Roman citizens in Italy were relieved of the direct war levy from 167 BCE, which is one of the clearest statements of what conquest was for.
Indirect taxes — customs dues at provincial boundaries, a tax on the sale of slaves, a five per cent duty on inheritances — fell more widely.
How it worked
Under the Republic the right to collect certain taxes was auctioned to companies of publicani, who paid the state and kept what they gathered. The system delivered revenue without a bureaucracy and produced the abuses one would expect.
The treasury proper, the aerarium, was in the temple of Saturn under the quaestors and the Senate's control. Under the emperors the fiscus — the imperial account — grew alongside it, and the boundary between imperial and public money was never made clean.
Powers and limits
Collection depended on knowing what there was to tax, which is why the census and the provincial assessment matter more to Roman finance than any rate.
The Principate progressively replaced contractors with salaried procurators for the direct taxes, though contracting persisted for customs. The change is usually read as a gain in control rather than in fairness.
How it changed
Augustus reorganised provincial assessment and introduced the inheritance tax to fund veterans' discharge payments, which had been the fiscal problem behind a century of political crisis.
Diocletian's reform recast assessment on units of land and labour, with periodic revisions — a system that made the tax bill predictable to the state and heavy in a way the surviving complaints make plain.
What the evidence supports
Citizens in Italy paid no direct war levy after 167 BCE.
Attested in the historical tradition and connected explicitly to the wealth taken from Macedon.
Tax collection was contracted to private companies under the Republic.
The publicani are documented in inscriptions, in Cicero's correspondence and in the legislation regulating them.
Total imperial revenue cannot be calculated.
No budget survives. Modern totals are constructed from army pay, coin output and assumed population, and vary by large factors depending on the assumptions.
Terms
- tributum
- Direct tax on land or persons, levied in the provinces.
- publicani
- Private companies that bought the right to collect certain taxes.
- aerarium
- The public treasury in the temple of Saturn, under the quaestors.
- fiscus
- The imperial account, whose boundary with public funds was never fully defined.
Primary sources
Cicero, Letters to Atticus 5-6
A governor dealing with tax companies and provincial debt in Cilicia.
Augustus, Achievements of the Divine Augustus 15-18
Payments made from the emperor's own account, as the emperor wished them recorded.
Tacitus, Annals 1.11, 2.42
Provincial complaints about tribute, and the accounts left by Augustus.
Covered elsewhere
- Recruitment and terms of military service is treated in the warfare encyclopedia: Recruitment. The property qualification, professionalisation, and the citizenship granted on auxiliary discharge are covered as military institutions.
How to read the evidence labels
- Evidence level: Documented
- Supported by a named primary text or by excavated material evidence.
- Evidence level: Probable
- Supported by strong inference that most specialists accept.
- Evidence level: Disputed
- Substantial specialist disagreement exists; competing readings are stated.
- Evidence level: Literary
- Belongs to poetic or mythological construction rather than to history.
- Evidence level: Mythological
- Belongs to shared religious or mythic tradition rather than to any single text.
- Evidence level: Unknown
- The available evidence is insufficient to decide.
These labels describe the status of the evidence, not our confidence in a conclusion. A claim marked Literary is not a claim we doubt; it is a claim about what kind of thing a poem is.