[2] Such a generalisation does not reflect actual past legal practice, but can only show which general principles are likely to have been typical for many (but not necessarily all) early Celtic laws.
They remained at all times private persons, not public officials; their functioning depended upon their knowledge of the law and the integrity of their judicial reputations.
Some evidence can be gathered from the 'usual suspects', like Caesar's De Bello Gallico, who discusses some aspects of Celtic laws in his account of the Gaulish Wars, specifically his famous excursus on the Gauls,[6] but also in some other passages.
[9] Besides some references in classical authors, there is a small number of texts in Iron Age Celtic languages, some of which (may) contain legal information, too.
The most clearly legalistic sources are the Celtiberian inscriptions on Bronze tablets from Contrebia Belaisca (Botorrita), dating from early after the Roman occupation of this area.
[10] Botorrita IV might even start with a legalistic formula, '[ tam : tirikantam : entorkue : toutam [|] : sua kombal[ke]z : ...'[11] which could perhaps be interpreted as '...the senate and the people have decided...',[12] mirroring the Roman equivalent.
To some degree, exceptionally short pieces of textual evidence in Celtiberian also allow to gain some information about what possibly could have been a widespread Celtic legal practice.
From Spain, a number of so-called tesserae hospitales, 'hospitality tablets', are known, inscribed in Celtiberian, often with no more than a single word, occasionally with very short sentences.
Given that many, if not most of them come with an internal Celtic cognate terminology, it is unlikely that they actually are late loans from e.g. Roman provincial law, although some crossovers in legal customs should be assumed.
The importance that ancestry had for the late prehistoric Celts is stressed by several classical authors,[16] and seems – at least for some areas, in some periods – also be confirmed in the archaeology by the effort put into burials.
[17] The structure of Celtic kin-groups can be reconstructed to some extent,[18] but little of internal kinship relations will have been formalised in a way that could be considered law.
Inheritance seems to have been passed on primarily in the paternal line,[23] as such, clarifying the relations between partners, who probably quite frequently were members of different kin-groups, as well as their children, must have been quite essential.
[26] Given the detail given to different kinds of sexual union in early medieval Welsh law, it seems reasonable to assume that polygyny was also common in Wales some time before the law-texts were put into writing.
It is likely that there were other elements covering various issues of kinship relations in early Celtic laws, for instance covering adoption, expulsion of antisocial kin members, and inheritance rules in case that a whole lineage would be heirless, but there is too little available information on this subject from late prehistory to allow for more than a generalisation of similarities in these areas as found in early medieval Irish and Welsh law.
As Caesar reports that the leaders of the Gaulish factions are those with the greatest influence, whose opinion is most highly thought of,[41] it is quite likely that such differences in rank also had consequences in legal proceedings, much like in the Irish case.
[42] The regulation of contractual relationships is one of the most important elements in any legal system, and especially so in societies where there is a lack of a strong central state, enforcing codified law.
Where Celtic societies in late prehistory are concerned, all evidence points to such an absence of a strong central state control, and a largely kin-based enforcement of legal claims.
As such, it is hardly surprising that some of the most obvious similarities, and the largest body of cognate terminology from late prehistory and between Irish and Welsh, in case of the latter two associated with parallel practices, exists.
[47] Historical texts also provide considerable evidence that later prehistoric contracts were secured with either pledges or sureties, the best example once again provided by Caesar, who reports that for the securing of a coordinated revolt against Caesar, the Gauls, "since they could not take the usual precaution of giving and receiving hostages, as that would have given away their plans, they asked that a solemn oath on their military standards be sworn, in which manner their most sacred obligations are made binding".
[48] That children of nobles were frequently used as hostages (i.e. pledges) in state contracts, also between Celtic and Germanic polities, is also well documented in the historical evidence.
One of the close similarities that exists between early medieval Irish and Welsh laws is a cooperative farming, particularly co-ploughing, based on contracts agreed between small farmers with too few oxen to set up a full ploughing team.
[51] Given that archaeology seems to indicate that the average late prehistoric farm in much of temperate Europe had about 5–10 cattle, of which at the most 2–3 would have been oxen,[52] and that Pliny reports that teams of up to 8 oxen were used on the heavier soils of the Gallia Cisalpina (with possibly even larger teams required for more northerly areas with even heavier soils),[53] it seems highly likely that similar regulations for cooperative farming practices were also common in many late Prehistoric Celtic laws.
[54] The significance of contractual relations in late prehistoric Celtic laws is also given away by an episode in Caesar's account of the Gaulish Wars, in his description of how Dumnorix, an Aeduan noble, had acquired his vast wealth: "for a great many years he has been in the habit of contracting for the customs and all the other taxes of the Aedui at a small cost, because when he bids, no one dares to bid against him".
What little there is to be found, again mostly in Caesar's account of the Gaulish wars, seems again to fit reasonably well with what we could reconstruct as ‘general principles’ from early medieval Irish and Welsh law.
[70] Given that at least some contracts most likely were entered into in front of witnesses and secured by sureties, it is also likely that these may have been called up to give testimony, also supporting their accounts by similar oaths.
This again would correspond well with the situation in early medieval Irish and Welsh law, where again cognate terminology exists for parallel practices of granting hospitality to foreigners.
Where the Celtic laws are concerned, it seems as if the guiding legal principles remained quite similar over an extended period, from late prehistory into the Middle Ages.
The focus on certain elements of the law, like those dealing with kin-group relations and contracts, makes it likely that these principles evolved out of the needs of still primarily kinship-based societies.
This development of a Celtic legal terminology seems to have taken place some time in later prehistory, with the conventional date given as roughly 1000 BC, even though this may be several centuries off.