Im currently finishing off the introduction to the book version of the translation of De divortio Lotharii regis et Theutberga reginae that Im doing with Charles West for Manchester University Press. So Ive been rapidly re-reading a lot of scholarship on the case and its outcome. Most historians have seen the result (that Lothar failed to get the divorce he wanted) as due to the weakness of Lothars case for separation from Theutberga and remarriage to Waldrada and/or the influence of outsiders opposing him, with Charles the Bald, Hincmar of Rheims and Pope Nicholas I taking starring roles as the preventers of divorce. Letha Böhringer has shown this probably isnt entirely fair on Hincmar (most recently in Letha Böhringer, “Das Recht im Dienst der Machtpolitik? Anmerkungen zu einer Neuerscheinung über die Scheidungsaffäre König Lothars II,” Mitteilungen des Instituts für Österreichische Geschichtsforschung 119 (2001), 146-154), but I want briefly to consider via a counterfactual an aspect that I dont think any of the scholarship has explicitly asked (Carlrichard Brühl gets nearest in “Hinkmariana II: Hinkmar im Widerstreit von kanonischen Recht und Politik in Ehefragen,” Deutsches Archiv für Erforschung des Mittelalters 20 (1964), 55-77). What if Lothar II had had Hincmar on his side?
So consider Lothar II with the assistance of Hincmar of Cologne, a man who is a skilled and knowledgeable canonist/propagandist, loyal to his own king and moderately devious. How does this Hincmar in 857/858 deal with his rulers desire to divorce his wife of two years and return to his mistress, against the Christian rules of marriage and without alienating some of his own elites and giving his uncles in neighbouring kingdoms a propaganda coup?
I think the key manoeuvre would have been trying to get Theutberga to co-operate right from the start of the procedure. Would that have been possible? Theutberga had to survive an accusation of horrible crimes against her (incest and unnatural intercourse with her brother, then aborting the resulting child) via a judgement by ordeal in 858. In 860 she was coerced into confessing the same crimes. Lothar II was unrelentingly hostile to her and I think had hoped to have her executed if the ordeal had gone against her in 858. While she wasnt necessarily infertile, she hadnt born a child in two years of marriage, suggesting either she was at least subfertile or that Lothar was so unenthusiastic that he wasnt sleeping with her frequently. (He eventually had at least four children by Waldrada, so any fertility issues must have been on Theutbergas side). And thered probably been a third person in their marriage from the start: its been reasonably assumed that Lothars involvement with Waldrada started before his marriage and continued after it.
What if instead of the accusations, in 857/858 Hincmar of Cologne had come to Theutberga and offered her a deal: that she should voluntarily agree to give up the marriage and enter a convent, in return for getting all the prestige of a royal abbess? Would Theutberga have been prepared to take that? She fought long and hard to regain her position as queen, but how much was that about clearing her name from widespread ugly rumours? By 868 after a failed attempt at reconciliation, she said shed rather “flee among the pagans that see the face of the glorious King Lothar”. How hard would she have fought to stay as Lothars queen, if shed been offered the change to be the next Radegund? I think theres a reasonable chance shes have accepted Hincmars offer.
Hincmars problem then would have been squaring Theutberga entering a convent and Lothar remarrying with canonical traditions of indissolubility. While one-sided separation to enter the religious life had been OK in early sixth century Francia, there were a number of authoritative texts available to Carolingian authors opposed to this: Gregory the Great, in particular had rejected this. Either both spouses had to agree to enter the religious life or neither could. There were one or two canons which did allow the spouse remaining in the world to remarry, but they were less prestigious texts. Lothar could still have run into difficulties.
But this is what he had Hincmar of Cologne for, a man who knew how to use authorities to get the result that he wanted. Gregorys argument was that since husband and wife were one flesh, part of it couldnt remain in the world while part didnt. But in the 860 case of Count Stephen of the Auvergne, Hincmar came up with the first ever “canonical” justification for why an unconsummated marriage could be ended and remarriage allowed. With the same argument, he and Lothar could have come up with a rhetorically fairly convincing story to put before the bishops and magnates of Lotharingia.
The argument would be that Theutberga had always wanted to lead a religious life, but had been forced into marrying Lothar by her brother Hubert. Lothar had, however, agreed to live in a chaste marriage with Theutberga, which they had secretly been doing for several years. Now, however, that was not enough for Theutberga: she wanted to leave the world completely. What was Lothar to do? Obviously, he wanted to support his wifes religious calling, but if he did so, it would mean he had to leave the world as well, leaving the kingdom defenceless. What could a poor king do?
With that dilemma placed before the magnates, Hincmar would then suggest his theory that because of non-consummation, Lothar and Theutberga had never really been one flesh, so the marriage could be ended (and he might even suggest the nice touch of the original dowry going to Theutbergas new convent as well). I think that combined argument might well have convinced the magnates. In particular, Theutbergas family and supporters would have got at least something of a payoff. They might be losing Königsnahe, but they would be getting access to a monastery (or maybe multiples ones) as a powerbase and source for precaria etc.
Could this have worked? The most difficult part might have been making Lothar II looking like a pious young man and keeping him away from Waldrada for a decent interval afterwards. And it would still have been difficult legitimating their son Hugh, if he had been born before 858, which is quite possible. But if Lothar hadnt made accusations against Theutberga, posing as someone of superior virtue, itd be a lot harder to start pointing the finger back and making accusations against him. In particular, the charge that he couldnt rule his wife/household wouldnt have been available. And consummation as required for a valid marriage was probably something that resonated with Carolingian audiences. Charles the Bald (and even Gunther of Rheims) would have had a lot less material to work with than the implausible and contradictory claims from 860 that take up so much of De divortio.
And what of the papacy? Theres been much stress on Nicholas Is interference in Frankish affairs, but even Nicholas didnt get involved unless hed been appealed to. And if Theutberga had been squared, who was there to appeal to him? Charles the Bald might have complained, but Hincmar would probably have retorted that it wasnt really his business. And if Nicholas had intervened, what would he have done? Dragged Theutberga unwillingly out of her convent, saying she had to return to her marriage? That would have been difficult logistically and would probably have been a PR disaster for Nicholas. Whatever his views, he may well have had to accept the situation.
The only remaining problem, of course, would probably have been an epidemic of other husbands in the archdiocese of Cologne trying to divorce their wives in the same way. (Fulcric has already tried something similar in the early 850s). But this is Hincmar of Cologne were talking about: he could almost certainly have found some semi-convincing argument for why Lothars case was an example that absolutely no-one else should ever follow.
So I think theres a plausible argument that the loyal Lotharingian Hincmar of Cologne could have arranged for his king to marry the woman he really wanted. And after that? If Lothar II hadnt had to keep trekking down to Italy to make his case to Rome, could he have avoided the illness that killed him in 869. Could Lotharingia have survived, rather than become a lost kingdom? That may be going too far. But I think there is a decent case to be made, that with Hincmar of Cologne on his side, Lothars divorce mightnt have been a lost cause.