I didn’t discuss Karl Ubl, Inzestverbot und Gesetzgebung: die Konstruktion eines Verbrechens (300-1100) (de Gruyter, 2008) as much as I should have done in my book-of-the-PhD-thesis Morality and Masculinity in the Carolingian Empire, even though I did have a section on incest. To be honest, that’s because Ubl’s book is long (nearly 600 pages) and it came out after I’d finished my original PhD thesis in 2005 so I didn’t rewrite the relevant chapter as much as I should have done.
So this is my very belated attempt to summarize and think more about Ubl’s ideas. Ubl’s book itself is now available open access (at https://www.degruyter.com/document/doi/10.1515/9783110210682/html?lang=en). There’s also a good summary of Ubl’s book in a review article by David D’Avray, “Kinship and religion in the early Middle Ages”, Early Medieval Europe 20 (2012):195-212 (10.1111/j.1468-0254.2012.00341.x), but that’s pay-walled.
In particular, in this summary, I want to show that Ubl’s work does not support the claim by Joseph Heinrich and other evolutionary biologists, economists and social scientists that one of the secrets of success of the West relative to other cultures was the Catholic church’s prohibition on cousin marriages. See, for examples of this argument:
Jonathan F. Schulz, Duman Bahrami-Rad, Jonathan P. Beauchamp, and Joseph Henrich. 2019. The Church, intensive kinship, and global psychological variation, Science 366 (6466):eaau5141 (10.1126/science.aau5141)
Joseph Henrich, The weirdest people in the world: how the west became psychologically peculiar and particularly prosperous (London, 2020)
The first thing to pin down when talking about cousin marriages is what we actually mean. One basic distinction is between first cousin marriage (when the children of two siblings marry each other) and second cousin marriage (when the grandchildren of two siblings marry each other). There are also further complications with more distant cousins and differences in the number of generations on each side, but those are less significant.
But this generalised definition of cousin marriage is one that applies specifically to Western Europe and other regions with bilateral kinship. Being one’s cousin (and incest taboos generally) is likely to be very differently understood in cultures which only recognise unilateral descent/kinship. For example, traditional Chinese customs barred marrying within one’ own surname (which descended in the male line). That restricted marriage to some very distant cousins, but also allows marriage of a man to his father’s sister’s daughter (i.e. his first cousin). Reflecting this, many languages have different terms for parallel and cross cousins.
There’s also a further issue in the distinction between marriage prohibitions and marriage rules: are you allowed to marry your cousin or are you expected to marry your cousin? The effect of cousin marriage on social relations is very different if it’s a permitted option that one in a hundred couples may use or if 25% or more of marriages are with cousins.
506 and all that
Turning specifically to Ubl’s work, the article by Schulz et al cites Inzestverbot und Gesetzgebung, but it’s clear that the authors haven’t read much or any of it. You can see this by looking at Jonathan Schulz’ original 2016 working paper on the topic: “The churches’ bans on consanguineous marriages, kin-networks and democracy” (https://www.econstor.eu/handle/10419/163017). He doesn’t cite Ubl at all, but he dates the prohibitions on cousin marriage to the Council of Agde in 506. In fact, this council doesn’t have any provisions on incest, but a later canonical collection, the Collectio Hispania, added as an appendix to the canons of Agde some canons from the Council of Epaon in 517, which did ban first and second cousin marriage. (as Ubl discusses on pp. 201-203). Schulz et al in 2019 do cite Ubl, but in their supplementary text (p. 8) they still date prohibitions on cousin marriage to the Council of Agde in 506.
Ubl also makes it clear right at the start (pp. 4, 11-13) that he doesn’t think the church as an institution was opposed to familial relationships or wanted to prevent people reinforcing kin ties. That’s precisely the claim that Schulz, Henrich and others are making in their Research Article Summary of the 2019 article, that “historical research suggests that the Western Church systematically undermined Europe’s intensive kin-based institutions during the Middle Ages”. It’s pretty clear from that they’re relying on the views of Jack Goody about the reasons for incest prohibitions, which have repeatedly been rejected by medievalists. What Ubl instead provides is a detailed account of how contingent the route was to the extreme incest prohibitions of the eleventh century West.
Counting relatives
Ubl starts (Chapter 1) with the vexed question of how the closeness of relatives was counted (pp. 14-27) and argues that almost everyone before the eleventh century was using the Roman method of counting. If you’re someone’s relative you share a common ancestor. In the Roman count you count back the generations from yourself to your common ancestor and then forward the generations from them to your relative. So your first cousin is a 4th grade relative:
My parent (1)
My grandparent (2)
My parent’s sibling (3)
My first cousin (4).
This can sometimes also be written as 2-2 related (counting the up and down links separately). In this system second cousins are 6th grade (3-3) related.
The one main person who didn’t use this way of counting was Gregory the Great. He used what would become the canonical count, which just counts back the generations to the common ancestor. In this system, first cousins are 2nd grade related and second cousins are 3rd grade related. Some Carolingian sources followed Gregory and some stuck to the Roman count, but the resultant confusion didn’t really matter because this was more a matter of judicial theory than legal practice (p. 26).
Similarly, even when early medieval councils (such as the Second Council of Toledo in 527×531) and popes produced regulations saying that you could not marry any relative, they were probably using the Roman law idea of any relationship ending at the 6th or 7th Roman grade, so there was little effective difference from a prohibition against second cousin marriage (pp. 200-201). I’d add that in practical terms until you have written genealogies/family trees, which only come in for non-royal families in the tenth century, you’d probably be doing well if you know all those who were your second cousins. Even now, I doubt many people could name all of their eight great-grandparents, which you would need to check to be sure if someone was your second cousin.
Incest in the Roman world
Ubl in Chapter 2 looks at Roman traditions. He starts with Roman secular law and points out (p. 38) that there’s little evidence of a ban on second cousin marriage in the early Roman republic (the only evidence suggesting this comes from much later). He also mentions, as an important aside (p. 41), that bilateral incest restrictions don’t fit well with an early Roman culture dominated by agnatic (male-line) relations.
We can see examples of first cousin marriages happening from 200 BCE onwards in the Roman republic (p. 42). On the other hand, the Romans did disapprove of very close marriages (condemning the Persian and Egyptian acceptance of sibling marriage). The first emperor to legislate on incest was the pagan emperor Diocletian in the late third-century CE. His ban was only on most types of uncle-niece marriage, but he uses a lot of moral rhetoric, describing incest as against divine order. Ubl cites Henry Chadwick arguing that Diocletian’s moral rhetoric is implicitly anti-Persian. He also points out that Diocletian ignored existing Roman law banning marriages between adoptive relatives when creating his Tetrarchy (pp. 43-46).
When fourth-century Christian emperors and church councils discussed incest restrictions at all, their focus were uncle-niece marriages, levirate marriages (a man with his brother’s wife, after the previous marriage had ended) and sororate marriages (a man marrying his wife’s sister), which Jewish law allowed, but Christians (and in some cases pagans as well) were increasingly opposed to (pp. 48-55).
Theodosius I in the 380s or 390s regulated on marriage with a brother’s wife or a wife’s sister, but also produced a law against (first) cousin marriage. The text of this second law doesn’t survive, but it was regarded positively by some pagan contemporaries as well as Christians. Ubl argues that the law is Christian propaganda by Theodosius and was probably influenced by western bishops, who reinterpreted Biblical precedents to justify prohibitions. The fact that the law foresaw imperial dispensations allowing such marriages, and that occasionally such marriages continued into the sixth century in Italy suggests the law may have been partly symbolic (pp. 56-66). On the other hand, the closest western imperial marriage we know of in the Theodosian dynasty itself is a first cousin once removed (Licina Eudoxia, the grand-daughter of Arcadius, marrying Valentinian III, the nephew of Arcadius) (p. 74).
So this suggests a west-east split on cousin marriage specifically in the fifth and sixth century. Theodosius’ law was abolished by the eastern emperor Arcadius in 405 (p. 65) and cousin marriage remained acceptable in the Eastern Roman empire. Justinian didn’t prohibit it, though he added other marriage restrictions, such as godfathers and goddaughters marrying (pp. 66-70).
Incest in the post-Roman west
Chapter 3 of Ubl starts with the vexed question of how exogamous or endogamous the early “Germanic” barbarians were and argues against Jean-Pierre Poly’s claim of endogamy and matrilineality, which Poly based on an interpretation of some provisions in Salic law. Ubl shows that the kin of a married couple are largely considered separately by this lawcode (which argues against close endogamy). Ubl also points out that all the incest prohibitions we find in barbarian laws are derived from Roman and Christian traditions (pp. 78-84).
Ubl then goes on to point out that we know of very few cases of cousin marriage in the Merovingian period, or the marriage of any blood relatives, whereas we do know of a number of cases of marrying affines, normally in order to maintain/create an alliance: men marrying their brother’s widow, or two sisters, or a stepmother or an uncle’s wife (pp. 84-102). Rules and behaviour on affines are where the difference is between late antique Western Roman and Frankish practices: neither of them are normally marrying their (first) cousins (pp. 102-103). Ubl has a nice illustration of this using Cassiodorus, Variae 7, 46, which is a formula allowing for cousin marriage at the dispensation of the ruler (Theoderic the Great) (p. 107).
Having looked at practice, Ubl then goes back to law in Chapter 4, and the first big expansion in the West of incest prohibitions with the Council of Epaon 517, which extended marriage prohibitions to second cousins and the Lex Burgundionum which excluded all blood relatives. Ubl sees the driving force for these laws as bishop Avitus of Vienne, making a conscious innovation to Roman law and probably envisioning the marriage ban as extended to all Roman-connected kin (6th grade, Roman count). Avitus does seem to have been motivated by a desire to control laymen and show episcopal might (pp. 120-137).
However, it’s important to note is that this was all taking place in the kingdom of Burgundians, which got conquered by the Franks less than 30 years later, so there was no automatic effect of these laws on Frankish practice. Merovingian councils do, however, start repeating the Council of Epaon prohibition on second cousin marriage after the Frankish conquest of Burgundy and by the time of the Council of Orléans 538, it’s applying to all of Francia (pp. 137-152). There were continued arguments over what the penalties should be, but there’s a fairly united Merovingian church view by the end of the sixth century (p. 167). Ubl thinks the Merovingian church took up the Epaon provisions both to keep up Roman traditions and to show the power of bishops (p. 171-174).
So far, this starts to look a bit like Goody’s thesis about the Western Church flexing its muscles, even if he’s got the specific dating and the motives wrong. But Ubl then goes onto look at Merovingian secular law (both lawcodes and capitularies) and shows that some Merovingian rulers also legislated on incest, with penalties tending to increase over time. He thinks this is mainly about rulers trying to signal their Romanness and points out that the Merovingian state didn’t actually have the means to enforce incest prohibitions (pp. 176-190).
Ubl then backtracks a bit chronologically to look at Visigothic law (pp. 191-211). The Breviary of Alaric II from 506 shows Alaric (an Arian) continuing Roman incest rules, including the ban on first cousins marrying. But the first Visigothic church council to deal with incest was the 2nd Council of Toledo 527/531 which banned marriage to any blood relative. Ubl thinks this was based on Roman-style six degrees of relationship as the limit and may have been influenced by Epaon 517. Bishop Montanus of Toledo was also trying to strengthen his position as metropolitan and was possibly connecting incest to Priscillian heretics. But generally, in the Visigothic kingdom it was secular rulers rather than the church legislating on incest.
Ubl’s overall argument about the post-Roman and pre-Carolingian situation is that there was no overall legal authority and no central programme of the western church. Instead, you have a combination of rulers legislating on incest to prove their Romanness and bishops (sometimes just individual bishops) wanting to exert their authority. He thinks that the legislation was mainly symbolic and that where you see resistance/cases of incest, it’s more often concerning affines than blood relatives (pp. 211-213). But Ubl also argues that in a post-Roman west where state structures were much weakened, exogamous marriages by the aristocracy were one of the few ways of maintaining transregional links and that aristocrats themselves welcomed the stabilisation this provided, even if it was also an irritation to be told what to do by bishops (pp. 213-215).
Carolingians
Ubl in Chapter 5 discusses the early Carolingian engagement with incest. But he actually starts in the early eighth century with the Anglo-Saxon missionary to the Franks Boniface getting confused about Gregory the Great’s advice for the English mission from the late sixth century. Gregory, in the Libellus responsionum to Augustine (which Ubl thinks is genuine) used a different method of counting relatives from the Roman one: Gregory’s canonical count (see above) made first cousins 2nd degree rather than 4th degree related. Gregory banned the marriage of first cousins but allowed the marriage of second cousins. Gregory was modifying eastern Roman secular law, which allowed first cousin marriage, and simply ignored or didn’t know about Frankish and Visigothic councils (pp. 219-224).
As this shows, the idea that there was a unified church position on incest doesn’t hold up. To add to the confusion, some Irish synods down to 700 CE or so were still saying that only the prohibitions in Leviticus were valid, not extensions of them (pp. 230-231). The English church were following Gregory the Great’s ban on first cousin marriage, but hadn’t banned marriage to two sisters, as on the Continent (p. 232).
Boniface several times wrote plaintively to the papacy about what the rules should be. His initial advice came from Pope Gregory II who at the Synod of Rome 721 had banned godparents marrying godchildren (influenced by Byzantine legislation) and also banned marriage to any known relative (influenced by the 2nd Council of Toledo). But Gregory II told Boniface that as a concession to the newly converted, they could marry after four “generationes” (pp. 236-240). Boniface also later got advice from Pope Gregory III, who said that the prohibitions extended to the 7th grade (which Ubl thinks was by Roman count, up to second cousins once removed) (pp. 236-237). Between the different and unspecified methods of counting, uncertainty over whether some documents were authentic and new regulations, it’s not surprising that Boniface was confused.
Ubl then looks at the early Carolingian rulers. Pippin’s legislation started off slightly more permissive than the papacy’s bar of up to 7th Roman grade ban but ended up with the same limit. He also enacted restrictions on godparent marriage (pp. 257-269). Charlemagne’s main concern wasn’t extending limits but enforcing incest laws. He developed both the idea of episcopal visitations round the diocese with enquiries about incest and that of the parish clergy checking relatedness before marriage (pp. 270-285). Ubl contrasts Pippin’s “symbolic” enactment of incest laws to show royal power and godly order with Charlemagne’s practical attempts, which he links to the extension of the Carolingian empire and efforts to create a “Reichsaristokratie” in which nobles married across regions (pp. 289-290). (Ubl doesn’t, however, agree with Régine Le Jan that the Carolingians were trying to destroy clusters of noble kin groups which sustained themselves by repeated marriages with one another).
Chapter 6 discusses varied responses by intellectuals within the Carolingian empire to incest. As Ubl points out, the five councils ordered by Charlemagne for 813 still had different definitions of who counted as a relative based on which bits of canon law they cited (pp. 292-293). Canon law collections which collected together contradictory canons from a variety of periods probably added to the confusion (pp. 297-298). And not all Carolingian churchmen agreed with the papacy on how far the limit should extend: Hrabanus Maurus thought that only marriages within the 4th Roman grade or closer (first cousin marriage) should be separated, while those in 5th grade marriages should do penance, but had their marriage remain valid (pp. 310-315).
Ubl also discusses the actions of the separate forgeries of Pseudo-Isidore and “Benedict Levita”. He reckons “Benedict Levita” was considerably more interested in incest than Pseudo-Isidore and aiming to create consistent statements about the 7th grade as the limit (pp. 329-335). On the other hand, he thinks it’s the Pseudo-Isidore workshop, in reaction to Hrabanus Maurus, who produced a forged letter of Gregory the Great, trying to invalidate his Libellus. “Gregory” tells Felix of Messina that the rules allowing 4th grade relatives to remain married were just intended for the newly-converted English, and the normal prohibited limit for blood relatives and affines was the 7th grade (pp. 337-340).
Ubl thinks Hincmar was relatively unimportant for the canonical tradition on incest and mainly significant as a transmitter of Pseudo-Isidore’s anti-Libellus forgery (pp. 341-342), though he did play a prominent role in several alleged cases of incest, including those of Theutberga and Count Stephen (pp. 345-356). Ubl sees Regino of Prüm as having a longer-lasting effect on the canon law of incest via his combination of Carolingian decisions and older canons (pp. 359-360). One particularly important decision that Regino relays (via several Frankish councils) is from Pope Nicholas I, saying that you can’t marry any blood or other relative as far as records or memory extends (pp. 362-363) with no generational limit.
But alongside Nicholas I’s decision and other papal ones saying that no relatives can be married, Regino also includes other texts which show the 4th grade of relationship as the debatable boundary, without making clear whether he’s using the Roman or canonical count. The Roman count would allow anything beyond first cousins as acceptable, so Ubl thinks it’s more likely that Regino was using the canonical count, making third cousins the final non-acceptable relationship (pp. 366-368). Regino also has details of episcopal visitation practices, which provided norms for these, at least for east Francia (pp. 372-373).
Ubl overall doesn’t see the Carolingian church’s demands as excessive. Most of the rules are either showing a limit of 7th Roman grade or 4th canonical grade, making the outer limit of the ban either second or third cousins, depending on whether the grade is taken as exclusive or inclusive and the exact method of counting. The differences were thus fairly marginal between East and West Francia, although there were different views in individual cases (pp. 374-377). The majority of the Carolingian incest cases brought to judgement concerned affines (9 out of 14) and the two cases where we do know the degree of relatedness are 4-4 and 4-5 in Roman count. Some royal marriages were possibly 3-4, but there are no known 3-3 (second cousin) marriages in Carolingian Francia, whereas they were happening in late ninth-century Catalonia (pp. 373-381).
Ottonians
Because Ubl’s focus is on incest law, in Chapter 7 he goes onto the last high point of the state prosecution of incest, by the Holy Roman Emperor Henry II (1002-1024). He sees this as a key moment, when in the East Frankish realm, you get the combination of the canonical counting of relatives and the limits as the 7th grade, thus extending the prohibited relatives beyond oral memory (pp. 386-387). He thinks that this was by chance more than design.
The background to Henry II’s position was the second marriage of Robert II of France to his second cousin Berta in 996 (3-3 in Roman count). Ubl argues that none of the French elite were marrying within the Roman count limit of 7th grade, apart from Robert II (pp. 393-401) and that Robert’s other two marriages were exogamous by the Roman count.
Henry’s campaign against incest started at the Synod of Diedenhofen in 1003, when he complained about bishops not dealing with 7th grade marriages, highlighting that of Conrad I of Carinthia and Matilda. This was 4-4 by Roman count, but Henry II allegedly claimed it was 3rd grade by cousinship. This made a 4th grade relationship by canonical count (which might be seen as a borderline case) into one that was definitely an offence. Ubl argues that Henry II’s demand for 7th canonical grade was a way of emphasizing his new rank as emperor and distinguishing himself from the French kings, especially Robert II. In particular, it was a way of demonstrating oversight over his bishops (pp. 404-413).
The long-running case over the marriage between Otto and Irmingard of Hammerstein, which involved Henry II, his successor Conrad II and Pope Benedict VIII (1012-1024), showed that there were still arguments about grades, although this time the main initiative was taken by bishops (pp. 417-426). Burchard of Worms also altered canons in his influential Decretum to get an incest boundary of 7th canonical grade (pp. 426-427). Ubl argues that both Henry II and Burchard got their inspiration for 7th grade canonical count from a Carolingian forgery: Pseudo-Gregory’s letter to Felix. This text was included both in John the Deacon’s life of Gregory the Great and in an appendix to Regino of Prüm’s synodal book produced in Mainz, where Burchard had been treasurer (pp. 428-435).
Ubl thinks you can’t separate out the religious and political aspects of Henry II’s incest campaign, but also wonders whether Henry had really thought of the wider social-political effects in preventing the highest nobility from isogamy. He thinks Henry in 1003 may have liked the thought of causing marriage problems for other descendants of Henry I (Henry the Fowler), the first Ottonian king, but that he was less interested in the topic after his own kingdom was secured. (pp. 435-440). And after Conrad II came to the German throne in 1024, who was married in a 5-4 marriage to Gisela, Henry II’s anti-incest policy wasn’t maintained (p. 442). There were some German bishops who tried to object to this and other distant relationships, but not many and the papacy didn’t object (pp. 444-451).
The change to the papal view came when Peter Damien got involved in 1044, which was never good news for anyone. He had the first detailed discussion of the way of counting problem since the eighth century and argued for the canonical count. Ubl argues that it was Peter Damien’s opposition to sex generally that led him to support an incest ban even at non-visible levels of relatedness (pp. 451-458). Leo IX in Rheims at 1049 was already condemning some “incestuous” marriages in France, where they were still adhering to the Roman 7th grade limits, but he was also probably giving dispensations (pp. 462-467). Such dispensations continued under subsequent popes, even when Pope Alexander II made the canonical count official church law in 1059 (pp. 468-470). These extreme limits only lasted until 1215, when Innocent III at Lateran IV reduced them back to 4th canonical grade to avoid misuse by nobles seeking to end their marriages (pp. 473).
Causes
Ubl thus argues against seeing the extreme extensions of incest rules as due just to the “dark machinations” of the papacy: the extension came initially from Henry II and Burchard, and what the papacy eventually got from them was more a symbolic control over marriage than actual material rewards (pp. 475-476).
Overall Ubl argues that there was no continuous development of incest prohibitions. Instead he sees two key moments in the early medieval history of incest law: when Avitus of Vienne around 500 said all marriages within Roman-defined relatedness were incest, and around 1000 with Henry II and Burchard, bringing in the 7th canonical grade. Avitus saw bishops as taking over Roman emperors’ tradition of incest prohibition but didn’t feel bound by political realism as they had been (pp. 479-480).
In the East, meanwhile, (first) cousin marriages were only banned in 692 and drastic penalties for first and second cousin marriages were only introduced by Leo III in 741, at a time when he was trying to stabilize the Byzantine Empire. Leo III’s Ecologa prohibited marital separation, in contrast to the Quran’s legitimation of polygamy, divorce and cousin marriage (pp. 480-484).
Ubl thus sees in both Western and Eastern Europe two movements for the extension of incest rules. The first was a move to more symbolic and aspirational laws, trying to create Christian societies. The second, from around 1000 gave unlimited competence of the church over marriage law. It was only in the eleventh century West that the church took a distinctive route, with the papacy taking up extreme incest rules as part of creating its own legal system (pp. 484-487).
Ubl specifically doesn’t see western incest rules as hostile to the nobility (p. 488); he sees a functionalizing of the incest rules in the eleventh and twelfth century benefitting both the church, in asserting its competence over marriage, and the nobility, in getting separations where required (pp. 489-490). But Ubl doesn’t see incest prohibitions as fully explained by functionalism, since while some exogamy may increase social integration, too extreme prohibitions are dysfunctional (pp. 490-492). Functional theories also presuppose a static society unified in its interests, which medieval societies weren’t (p. 492). Instead, the actions of a few individuals had a surprisingly large effect (p. 493).
Overall, Ubl doesn’t see much resistance by “Germans” or any others to incest rules until the eleventh century. Instead, bishops promulgated rules to establish themselves in the social order and kings to show themselves Christian rulers. It also brought the possibility of regional integration and social mobility by preventing regional or social elites from just marrying each other (pp. 495-496).
Ubl finally rejects Jack Goody’s argument that incest prohibitions led to the rise of the European nuclear family (which has also been seen as part of the cause of the “rise of the West”). You can already see nuclear families as the normal structure in the late antiquity west, and as Michael Mitterauer points out, Eastern Europe combined wide incest prohibitions with patrilineal clans. Instead, extensions of incest provisions came earliest in areas with traditions of Roman law (Gaul, Spain, Francia, Byzantium) and only later in regions without much Roman heritage (Ireland, England); their main function, if not their justification, was to hold together societies in the post-Roman world (pp. 496-498).
Cultural change
As my summary shows, Ubl describes a complex story, a punctuated equilibrium where secular rulers and individual churchmen have an outsize role, rather than the steady programme of a collective “church”. For that reason, I suspect his results will often continue to be ignored even by research that cites him.
But for my interests in how moral and cultural change happens in the premodern world, Ubl’s book gives a useful paradigm. Firstly, it shows that a punctuated equilibrium of cultural stability is normal. Institutions are created that are “sticky” and don’t change much, even as other aspects of society change substantially. Then there’s suddenly a mismatch where a rapid change may be required, such as when the Roman emperors’ power to legislate over incest suddenly disappears with them.
Secondly, the history of incest regulations reveals both churchmen and rulers as creators of change (and once again demonstrates the fact that a few oddball religious figures can have an outsize influence – I don’t think even many early medieval specialists tend to think much about Avitus of Vienne). Thirdly, it reminds us how often legislation can be symbolic, without any real interest in enforcing it. I’m less and less sure whether that’s particularly characteristic of the early Middle Ages, however, as it seems to be increasingly common in the twenty-first century.
Fourthly, once you had written authorities, whether canons or the Bible, one option was always to go back and reinterpret their ambiguities, while wrenching them out of context. Leviticus 18, for example, the foundational text of Jewish incest regulation, included both prohibitions on sexual activity with specific relatives and a prohibition on all relatives, either of which could be used or analogised.
Fifthly, legislation that’s mainly symbolic often refers to practices that aren’t socially common or that are seen as characteristic of other, despised societies. For most of the Roman and early medieval periods, there isn’t much evidence of a widespread desire for cousin marriage; instead, nobles managed prestigious marriages while tracking just about on the right side of the prevailing degree line. Sixthly, there’s often at least some benefit for some of those on whom restrictions were laid. Although Ubl doesn’t discuss it much, when the Carolingians did try and enforce incest provisions, that gave additional power to community elders, who got to tell the younger generation whether or not their marriages were valid based on oral memory. I’ve suggested elsewhere (https://www.brepolsonline.net/doi/abs/10.1484/M.HAMA-EB.5.129267) that it may have been the village elite more generally who got to control marriages in the locality under this premarital inquisition regime.
And finally, in this period decisions on incest regulations were always made by men, rather than women, but they didn’t necessarily benefit all men or even all elite men. Men’s interests didn’t always coincide and there are examples of women taking advantage of the incest rules, mainly, although not entirely, using spiritual kinship, which was more easily manipulable. Rather than a grand functionalist view of incest regulations (or other ones) we probably need to look more closely at specific interests at specific times.
Magistra et Mater 