The Romans obviously conquered Ireland's nearest neighbor, Britain (at least the southern part of it), but they seem to have stayed away from Ireland, at least as far as I am aware.

Is this the case, and if so, why did they abstain from military involvement in Ireland, when they were already in Britain, only a few miles away?

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    starting point: en.wikipedia.org/wiki/Hiberno-Roman_relations
    – two sheds
    Commented Aug 15, 2015 at 11:53
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    Can you clarify what you find insufficient with the Wikipedia article's section on Roman military in Ireland (c.f. two-sheds' link)? Is there a reason why Romans should be military involved in Ireland?
    – Semaphore
    Commented Aug 15, 2015 at 11:57
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    @Semaphore 1) meta.stackexchange.com/questions/8724/… 2) The comment followed my question, not vice versa. 3) Why wouldn't Rome invade Ireland? They invaded everything else. You might as well ask why Rome ever expanded beyond the original borders.
    – Wad Cheber
    Commented Aug 15, 2015 at 12:05
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    (1) What's the relevance? (2) So? You have an edit button. (3) I didn't know the Romans invaded India, but that's besides the point. A why-didn't-x-happen question ought to explain, however briefly, why one might expect x to happen.
    – Semaphore
    Commented Aug 15, 2015 at 12:24
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    Actually, the Romans didn't even conquer Scotland. Commented Aug 16, 2015 at 17:00

3 Answers 3


Ireland was not a threat to Rome

By the time the Romans had reached Britain, their empire covered most of western Europe and their resources were becoming stretched. For most of the time they spent in Britain, they were more concerned with holding on to what they had rather than expanding further.

Caesar invaded Britain in BCs 55 & 54 to see what was needed to stop the Britons supplying the Gauls with arms and men to fight and raid the Romans, the Romans were in Gaul because the Gauls kept raiding and robbing Italy, the Romans were in the rest of Italy because the other States kept raiding and robbing Rome.

Augustus effectively put a limit on the Roman boundary, for logistical purposes, Claudius invaded Briton some years later because there was Tin and also the Britons were still causing a nuisance to the Romans in Gaul.

There were no regular raids from Ireland, also it didn't have a specific resource that Rome needed, whereas Britain had Tin, Lead, and other developed mineral mines that were useful for Roman Empire traders and commerce.

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    You could also probably invoke internal Roman political reasons. For instance Claudius' motivations to posture as a legitimate heir to his predecessors in the Julio-Claudian dynasty in the case of the conquest of Britain in 43AD. How would have the conquest of Hibernia been perceived by the Senate? Worth conquest?. Remember Simon Schama's opening meme: "From its earliest days, Britain was an object of desire. Tacitus declared it pretium victoriae – 'worth the conquest', the best compliment that could occur to a Roman. Commented Aug 15, 2015 at 13:08
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    @AlainPannetier We were actually just discussing this subject last week in my summer study group. You added some very valid points. Thank you. Commented Aug 15, 2015 at 13:18
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    @AlainPannetier, Tacitus was hardly going to say that it wasn't worth having: that would have been an insult to his father-in-law. Commented Aug 15, 2015 at 20:50

To invade Ireland, the Romans would first have needed to gain full control of either Wales or the Clyde estuary in Scotland, something they never succeeded in doing.

The Romans very much wanted to conquer Ireland, because the Irish were a constant source of weapons and "rebellibus" support to the Scots and Welsh for attacks on Roman communities. During the fifth campaign of Agricola he reached partem Britanniae quae Hiberniam aspicit (the part of Britain that faces Ireland), but he never controlled it sufficiently to attempt a crossing.

During his invasion of Scotland, Agricola had to build a large number of forts, which has been great for archaeology, but not so great for the Romans, since it became very expensive to fend off the Gaels. This was the same in Wales, where a string of costly forts had to be maintained to protect against Irish-sponsored attacks. The graphic below, showing Roman and Gaelic forts, illustrates the line of control:

forts in Wales

The green and violet is Roman; red, blue, yellow and orange Gaelighe. Although the large number of green dots suggest Rome might have controlled most of Wales, this is not the case. The solid line of control were the "castles" (the violet dots on the right), which were Chester, Wroxeter, Lanchester (mispelled as "Kanchester" in the map) and Gloucester. The other forts were in "allied" territory, which was semi-autonomous and not under full control (hence the need for lots of forts). The orange line of "Offa's Dyke" (a structure of uncertain history, shown on the map) shows where Roman authority more or less ended.

The Gaels were very keen to control the area because there are a lot of tin mines there, which is needed to make bronze, their main weapon material.

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    I think you mean Worcester, not Colchester. Colchester is in Essex, on the other side of England.
    – Mike Scott
    Commented Aug 15, 2015 at 19:20
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    This is very interesting but I am a bit puzzled by the notion of Gaelic "forts". As far as I know, they did not have the kind of strong centralized authority which is usually needed to ensure that so many forts are built, maintened and manned. What is the source of the graphic? +1 anyway for the new angle! Commented Aug 18, 2015 at 10:22
  • The Gaels used fortifications like anybody else. Roman forts were originally based on the Gaelic fort design, though square instead of round. The Gaels had a high king (Ard Righ) and there was also usually a king of Albany (Scotland). Commented Aug 18, 2015 at 12:15

Ireland isn't "only a few miles away". The shortest sea crossings from Wales are Fishguard–Rosslare and Holyhead–Dublin, which are both 60 miles (100km). Scotland is closer: Portpatrick–Bangor is about 20 miles (35km). South-west England is about twice as far from Ireland as Wales is. The Romans never had sustained control of Scotland and didn't have control of Wales until around the time when they were already withdrawing from Scotland and consolidating behind defensible borders.

Also, these sea crossings are against the prevailing westerly winds and subject to bad weather at any time of year. There are strong currents and high tidal ranges. Crossing from Wales to Ireland is much more difficult than crossing from France to England and even that took multiple attempts.

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    This seems like arguing on a very minor and subjective point. From where I'm sitting, Ireland is several thousand miles away. This makes 60 miles "a few miles", relatively speaking. The distance between Rome and Athens is 13 times greater than the distance between Ireland and Wales, but they don't seem to have had trouble going back and forth between them. I'm not saying it would be a piece of cake, but it would be possible. The Irish used to row leather hulled boats back and forth between Ireland and Britain to capture slaves.
    – Wad Cheber
    Commented Aug 16, 2015 at 23:35
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    @WadCheber I don't see how your location today is relevant to the question of how easy it would have been for the Romans to invade Ireland nearly two thousand years ago. And you've ignored the point about territorial control not coming until they'd decided not to expand any more in the British Isles. Also, Rome to Athens is mostly coastal, which is much easier than sailing in the open sea, and in the Mediterranean, which is much more placid than the Irish Sea. Commented Aug 17, 2015 at 5:51
  • @WadCheber Also, an invasion is a very different undertaking to a raid. Commented Aug 17, 2015 at 6:16
  • My point was that relatively speaking, the distance between Ireland and Britain isn't that big. If it was considered worthwhile to invade Britain, the slightly larger distance shouldn't have been a problem significant enough to make invasion a non-option. If they wanted it badly enough, they could have done it.
    – Wad Cheber
    Commented Aug 17, 2015 at 6:58
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    The irish sea is not an easy sail, as noted above. I think you under-estimate the problems by focusing solely upon the short distance. @WadCheber Commented Oct 4, 2018 at 13:11

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