Way back in the day when I first started doing Charter A Week, I did a fair few posts on Boso of Provence. That was a while ago now, so for those who are just joining us, Boso of Provence was the erstwhile brother-in-law of the West Frankish king Charles the Bald. He married the daughter of the king of Italy, and enjoyed a meteoric rise to the top in the last few years of Charles’ reign, a prominence he more-or-less managed to keep up in the reign of Louis the Stammerer. After Louis died in 879, however, Boso ignored his two teenage sons and had himself declared king at the fortress of Mantaille by a congress of Burgundian and Provençal bishops. However, in 880 a combined force of Carolingian rulers led an army south to deal with him, taking Mâcon and besieging Vienne. Most of Boso’s key supporters abandoned him; and this is where we left him: late in 880, a neutered force, his support lopped off, destined to be a hedge-king skulking about the mountains of the French Prealps for the rest of his life. This is, I would venture to say, basically the standard story about Boso. However, since I wrote those posts, I’ve come across a few things and I’ve started to wonder whether Boso was less a spent force and more the Carolingian political equivalent of MRSA.
You see, after the success of the 880 campaign, the Carolingian rulers leading the army started to drift apart. Charles the Fat wanted to get to Italy to succeed his late brother Karlmann of Bavaria, and Louis III was panicked by reports that his northern army had met a serious defeat at the hands of a Viking force in Flanders. The end result was that they buggered off to do their own thing, leaving Carloman II to handle the anti-Boso action. And, with his support not entirely eradicated, he seems to have been able to slowly grow stronger and resist the Carolingian armies.(*) For one thing, it took another two years to take Boso’s fortified capital of Vienne itself. An attack in 881 appears to have done nothing, certainly not in terms of Boso’s support. Indeed, Regino of Prüm (writing a bit later) takes care to note that none of Boso’s supporters ever betrayed him to the Carolingians despite significant material inducement to do so. Archbishop Otrand of Vienne, one of his most important supporters, had gone so far as to imprison the bishop of Geneva. At the same time, Bishop Adalbert of Maurienne attacked and imprisoned Bishop Berner of Grenoble. These two bishops had been at each other’s throats for years, but it is possible that one or the other of them was a supporter of Boso, giving Adalbert his excuse for invasion.
With that said, Vienne was taken in 882, and the devastation was massive – a charter a few years later was dated by the ‘destruction of Vienne’. This left Boso reliant on the support of the mountainous provinces of eastern Provence, and that wasn’t a great base for launching any serious attacks on his opponents. Still, there are signs Boso had a resurgence towards the end of his life. In 887, Count Odilo of Die issued a charter dated by Boso’s reign as king. We also have signs that he was being sought ought by Provençal churchmen: around this time he issued a lost diploma for the church of Valence, and we also have evidence of grants to the churches of Vienne and Lyon (although it is possible that these might have been death-bed grants, it still implies there was enough of a tie there for these churches to accept some ideologically pointed gifts, such as crowns). If we’re feeling generous, there might even be some evidence from silence – despite his importance in the politics of the 870s and early 880s, Bishop Adalgar of Autun is conspicuously absent from the sources for the reign of Charles the Fat, which could possibly hint at his renewed support for Boso.
We also have a little bit of evidence for Charles the Fat’s response to this. Regino says that he allowed the Viking fleet which besieged Paris in 885-886 into Burgundy to punish a revolt against him there. This can’t be true of the bits of Burgundy the fleet actually went to – Sens, Auxerre, and Langres all show up as loyal to Charles in summer 886 – but it could indicate Charles knew about rumblings from Boso’s old heartlands in southern Burgundy and northern Provence. A more problematic, but potentially more interesting, source is a diploma of Charles the Fat for the church of Nevers, dating to 885. It claims to have been petitioned for by William the Pious, son of Aquitaine’s most important magnate Bernard Plantevelue. In the diploma, Charles recalls ‘the unbroken loyalty of [William’s] father Bernard… [who] with tremendous courage, inner strength, and unending loyalty set himself against… the tyrant Boso and his followers’, in the course of which battle he died. Now, as this diploma currently stands it is a forgery of c. 950-1100 (not least because we know Bernard Plantevelue was still alive in summer 886!). However, it’s a weird thing for a forger in the decades around the millennium to toy with – William and Bernard’s family had long died out by then, and their memory was kept, if anywhere, at Cluny (in the Mâconnais) or in Auvergne, not at Nevers. However, they had ruled Nevers back in the day, and maybe there was some information the forger had access to – otherwise, it’s a very odd thing to put in there, as it doesn’t serve the church’s interests and it doesn’t add formal authenticity to the document. If Bernard Plantevelue did die against Boso in autumn 886, then, it could be a sign that Charles was taking his old rival more seriously than historians have yet realised.
Boso never got the chance to do more, because he died in early 887. And there’s a lot of maybes in the above. Nonetheless, I think most of them are plausible maybes. Even then, even accepting most of them all they add up to is a slower decline in the early 880s and a bit of a recovery in the late 880s. Still, that’s more than he’s been allowed thus far. It also makes his career more explicable: rather than an enormous rise and catastrophic fall, it lets Boso’s kingship evolve more naturally, and more accurately reflects the Carolingians’ ultimate failure to crush him completely once they were in a dominant position.
(*) PSA: if your doctor proscribes you a course of antibiotics, be sure to finish it even if you’re feeling better before the end!