It’s sometimes suggested that the driving force behind King Lothar II’s efforts to divorce Theutberga was a desire to secure his succession. Lothar had no children with Theutberga, but several with his would-be queen Waldrada. But whatever Lothar’s motives had been in 857/8, the spiralling crisis of his kingdom in the 860s meant that any long-term concerns about his succession were overtaken by a more urgent problem, that of securing his political (and perhaps personal) survival. Lothar’s ‘solution’ to his marital problems was threatening his kingship in the here and now.
The best evidence for this is a letter written in the name of Lothar’s bishops and addressed to the bishops of Lothar’s uncle, King Charles the Bald (translated into English for the first time below). The letter speaks frankly. Lothar’s bishops state they have heard that unnamed people in Charles’s kingdom are advising him to depose his nephew. They call on their western colleagues to oppose this policy, out of episcopal solidarity but also because contrary to the rumours, Lothar’s kingdom was standing rock-solid behind him. The bishops declare that they have sworn oaths to Lothar which they have no intention of breaking; they admit that he has sinned in the past, but are now confident that he’s back on the right path.
Was Charles the Bald really considering instigating regime change? It is perfectly plausible. After all, Charles himself had nearly been deposed by his brother Louis ‘the German’ a decade or so earlier in 858, who had led an army into West Francia on the grounds that Charles was unfit to be king. Such an accusation could obviously be made against Lothar, thanks to the divorce ‘scandal’ which Lothar himself had initiated. And Uncle Charles was undoubtedly ambitious. The key factor was whether Lothar’s kingdom was divided. Would elements of Lothar’s followers welcome a new ruler, as elements of Charles’s followers had welcomed Louis the German in 858? This question explains the bishops’ insistence on their unity in the letter.
Of course we should be wary of taking this letter at face value. To begin with, the letter is not signed, so we do not know how many bishops were really standing behind Lothar. In fact, we do not even know that the letter was actually sent. It survives as part of the letter collection of Bishop Adventius of Metz, who might have been the text’s author; but we do not know whether the draft was discussed, let alone agreed and dispatched.
Yet it suggests that (at least one of) Lothar’s bishops in the 860s – the letter sadly cannot be precisely dated – were becoming anxious not about the indeterminate future, but about the political present. The rapidity with which Charles the Bald invaded Lothar’s kingdom on his nephew’s death in 869 has led some historians to wonder whether Charles had not pre-arranged a military assault, suggesting that the letter’s fears were not groundless.
One of the things that attracts me to studying (and teaching) Lothar and Theutberga’s divorce case is how much it has to tell us about the political order constructed by the Carolingian rulers, as it continued to evolve after the Treaty of Verdun in 843. The Carolingian dynasty’s grip on power was unchallenged in the 860s, but paradoxically that could be a problem for individual kings. If any Carolingian king would do, and yours was struggling, why not trade up for a better one? And if that was the way the wind was blowing, might it not be better to change tack early? One suspects that this prospect brought sleepness nights for Lothar, wriggling like a fish on the line he’d cast.
Image: Stuttgart Psalter
For blog posts relating to King Lothar II and Queen Theutberga, see http://turbulentpriests.group.shef.ac.uk/category/hst-3154/
For a list of translations available on this blog, see http://turbulentpriests.group.shef.ac.uk/translations/
 On the letter collection, see Charles West, ‘Knowledge of the past and the judgement of history in tenth-century Trier: Regino of Prüm and the lost manuscript of Bishop Adventius of Metz’, https://onlinelibrary.wiley.com/doi/abs/10.1111/emed.12138