This well-received YouTube video claims that Rome annexed Thrace in 45AD and then the Greek City State of Byzantium in 47 AD. Byzantium is also the last surviving Greek City State after the Rome annexed Massalia (nowadays Marseille, France), the Greek city, in 49BC.

Another well-received video claims a similar thing that Rome annexed both Thrace and Byzantium in 45AD.

I found written sources documenting the Thrace event; however, I find no reliable sources documenting the Byzantium event around 45AD or 47AD. Are there any reliable sources for the Roman annexation of Byzantium or any events related to Byzantium around approximately 47AD?

Clarification: I noticed that some other sources claim that Byzantium was a "fairly independent city" until 192AD. I am more interested in the events around 47AD (with an error of under ten years).

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    This could probably be cleared up if we weren't missing Book 10 and a large part of Book 11 of Tacitus' Annals. Other sources such as Suetonius and Cassius Dio do not seem to cover this in their accounts of Claudius' reign. Feb 18, 2022 at 2:25
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    Two important points: First, the Roman Empire (especially in its early days) was not at all centralized by our standards. Some writers have described it as a "federation of cities" with local affairs being entirely in the hands of the cities (as long as they paid their taxes and supplied soldiers!) overseen by an understaffed regional governor. "Annexed by Rome" and "Independent" didn't necessarily look all that different. Secondly, Byzantium was a fairly minor city-state. Constantinople was a much larger city founded on the same site.
    – Mark Olson
    Feb 18, 2022 at 12:36
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    @MCW I added "with an error of ten years" by editing the body of the question
    – dodo
    Feb 18, 2022 at 14:30
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    @MarkOlson Make sense. By saying "Annexed by Rome" and "Independent" didn't necessarily look all that different", are you implying that most cities under Roman rule are fairly independent? To my knowledge, for example, before 49BC, Massalia was very independent and not ruled by Rome: Rome even build a new city nearby to compete with Massalia. In 49BC, Massalia was conquered and lost its status of independence.
    – dodo
    Feb 18, 2022 at 14:41
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    Yes, annexed by Rome was quite independent. I can't think of a terse reference, but Brett Deveraux touches on this indirectly in his discussion of Roman institutions. IIRC, prior to Diocletian, the entire Roman bureaucracy for administration of the whole empire was smaller than my high school.
    – MCW
    Feb 18, 2022 at 14:48

1 Answer 1


The status of Byzantium most probably changed in 47AD, just somewhat, because of the Roman Bosporan War of emperor Claudius. After reading more about the conflict, I doubt there was any "annexation". Instead, the trend looks quite the opposite. The city probably got more freedoms after contributing heavily to the war effort.

Timeline of the Roman Empire I century AD

[During the Bosporan War] Byzantium [was] burdened with the significant tribute and possibly the sea carrying of Thracian cohorts and their supplies as the course of history of heavy burdens of this town has shown. Tacitus asserts that the inhabitants of Byzantium were exhausted by the late war in the Bosporus, so their tribute had been remitted by Claudius for five years (Tac., Ann. XII, 63)

  1. Source of the timeline of the Roman Empire
  2. Source of the citation: Gold Staters of Aspurgus and Mithridates iii and New Complexes with Coins and Jewellery Items from the Artezian Settlement (Abramzoon, 2017)
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    Maybe I'm missing something here but I can't see how the info presented points to 47AD. The Roman-Bosporan War is believed to have lasted from 45 to 49AD. Can you clarify the evidence that points to 47AD for the change in Byzantium's status? Feb 18, 2022 at 12:05
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    Thanks for asking for more precision. The Artesian fortress fell in autumn 47, after that the war for Mithriades was essentially over. Sure the timeframe for status change of Byzantium is not that precise, and would have happened "postquem".
    – James
    Feb 18, 2022 at 12:42
  • Very good sources! By saying "tribute had been remitted for five years", I think this implies that Byzantium was already paying a constant tribute in the past. May I ask when did the city start to pay the constant tribute?
    – dodo
    Feb 18, 2022 at 14:51
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    You do realize the Bosporan war involved pro- and anti-Roman factions in the Bosporan Kingdom at the Cimmerian Bosporus (i.e. the mouth of the Sea of Azov) and not the (Thracian) one Byzantium was on? Weaponsandwarfare.com explains that Claudius turned Thrace from some puppet kingdoms into a Roman province in 46 AD because of constant revolts in said puppet kingdoms.
    – Spencer
    Feb 19, 2022 at 17:01
  • Yes, you're correct. The Bosporan War was north of Black Sea. Because of Bizantium's location, sources point that the city was instrumental in providing shipments and support for the war efforts. I'm not aware whether Bizantium was ever part of the Thracian kingdoms. The Thracian Chersonesus, for instance, was not part of the province but lands of the emperor.
    – James
    Feb 19, 2022 at 19:00

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