A client kingdom was a state that kept its own king but answered to Rome. It owed support, often money or soldiers, and could not follow its own foreign policy. Client kingdoms are one reason the empire's borders are hard to draw.
Key takeaways
- A client state is one that is economically, politically and militarily subordinate to a stronger power, and Republican Rome was one of the most prolific users of them [1].
- Clients typically owed tribute and soldiers, and many were later absorbed as provinces [1].
- Judaea was a province from AD 6, after having been a kingdom under Herod the Great, a king named by the Roman Senate [2].
- The map has no client-kingdom layer, so these lands are a judgement call at the edges of each outline.
How client kingdoms worked
A client kingdom was a state that kept its own ruler but was subordinate to Rome. The general term for this is a client state: one that is economically, politically and militarily subordinated to a stronger controlling state, with shared but unequal obligations [1]. Republican Rome was one of the most prolific users of the idea. Instead of conquering a neighbour and absorbing it, it often made a client of it [1].
In return for being left alone, a client usually owed tribute and soldiers [1]. The king had to follow Rome's lead in foreign affairs, and Rome could install a king it preferred. Some clients were defeated enemies who were allowed to stay on their thrones. Others were allies that Rome helped into power, and Herod the Great is a well-known example of that second kind [1].
The system suited Rome. A friendly king could police a border region, provide troops and collect taxes, and Rome did not have to station its own governors and legions there. The cost for Rome was that a client could be unreliable, and a strong one might not stay friendly.
Many clients did not last. When a king died, or was removed, Rome could turn the kingdom into a province. Historians describe the policy as continuing up to the century in which the Republic gave way to the empire [1], and after that, individual kingdoms were gradually annexed one by one.
An example from our data
Judaea is a clear case. Herod was named king by the Roman Senate, and Josephus dates that to 40 BC, though Appian places it in 39 BC [2]. After his death the kingdom was split among his heirs, and when Augustus removed Archelaus in AD 6, his lands were merged into a province governed by a prefect [2]. Our data gives the province's annexation as AD 6, with its capital at Caesarea Maritima.
The outlines matter here. For AD 14, the map's extent is 3.67 million km², built from the provinces Rome held. Whether to colour a client kingdom as Roman is a judgement call, and it is one reason published sizes of the empire differ. The borders section of the homepage gives the short version, and the facts page lists the numbers we use.
The thing people get wrong
Many people picture the Roman Empire as a block of colour with a hard line around it. Client kingdoms break that picture. A client king ruled his own land day to day, so it was not a province in the usual sense. But Rome could depose him, and he supplied troops and tribute, so it was not independent either. Treating such places as simply "in" or "out" of the empire misses how Rome actually worked.
It is also wrong to think clients were rare. For a Republic that preferred not to annex its neighbours, they were a normal tool [1].
Client kingdom vs province
| Client kingdom | Province | |
|---|---|---|
| Ruler | A local king | A Roman governor |
| Owes Rome | Tribute and soldiers [1] | Taxes, collected for Rome |
| On our map | No separate layer | Drawn as a province outline |
Frequently asked questions
Was a client kingdom part of the Roman Empire?
Sometimes yes and sometimes no. The king kept his throne and his army was his own, but Rome decided who ruled and what the kingdom could do. That is why historians draw the edge in different places.
How did a client kingdom end?
Often by annexation. When a king died with no heir that Rome liked, or when a king was removed, the land could be made a province. Judaea is an example.
Are client kingdoms on the map?
No. There is no layer for them. Each year page says how its outline was made.
Sources
- Client state, Wikipedia.
- Herod the Great, Wikipedia.
- Ancient World Mapping Center, University of North Carolina.
- Every figure from our own map is worked out from the datasets on the data sources page (checked against Ancient World Mapping Center outlines and Pleiades).