One of the best things about doing research is finding pieces of evidence in the most unexpected places. I am back in Norway working on the Nordic Civil Wars project, thinking about how conflicts were resolved; what worked and what did not. As part of this, I have been reading Baglarsaga – chronicling the earliest years of the thirteenth century in Norway – looking for evidence of peace agreements. It was not the place I would expect to find any evidence for my forthcoming book on international law, but only two pages in, I realised I had struck gold.
One of the versions of Baglarsaga has a story about how King Sverre of Norway (r. 1177-1202) found out that there was a man in Denmark who was calling himself Erling, son of the previous King Magnus V Erlingsson (r. 1161-84), who, at one point, had been Sverre’s main rival for the Norwegian throne. Upon hearing this, and obviously realising that a son of his rival was a significant threat to his own position, Sverre sent men to Denmark to look for Erling, who promptly fled to the province of Göta in the kingdom of Sweden. Sverre then sent a letter to the Swedish king, Knut Eriksson, to whom he was related by marriage, and told him that ‘there was a man in his realm, who was calling himself a son of King Magnus, and who likely wanted to cause ‘ofrið’ (lit. unpeace) in Norway.’ As soon as King Knut heard this, he sent men to look for Erling and put him in the stone tower in the fortress of Näs on Visingsö – an island in lake Vättern – where he remained for a while (Bǫglunga sǫgur (1988), 2: 12).
The reason why this is of interest to me in writing about international law in the period up to c. 1200 is, as explained here many times before, that expulsion of individuals who were deemed dangerous in some way or another, and how these were tracked and chased across different political entities, is one of the best ways to see that international law was practised on a daily basis in the medieval period. Containing the movements of these people was of significant concern to rulers and, in many ways, was an extension of what can be seen in domestic laws from across the medieval West. We know something about how this was attempted because several treaties set out that neither side was to receive the men of the other without some form of identification that they came on legitimate business. Lists of ‘undesirable’ individuals were kept (e.g. Treaty of Falaise 1174), and we know that in certain contexts such lists were exchanged with the other side (e.g. Treaty of Colombiers 1189). We know that rulers could also intervene directly to canvass for the return of men who had been expelled, or to ask for them to be kept away. For instance, an eighth-century letter of Charlemagne to the Archbishop of Canterbury outlines the fate of Mercian exiles, asking the archbishop to intercede with the Mercian king, Offa, on their behalf so that ‘they may be allowed to return to their native land in peace and without unjust oppression of any kind’ (EHD I, no. 197).
The story in Baglarsaga evidently fits this wider context, showing how rulers could, and did, take action on this tricky issue. Of particular interest to me personally, is the imprisonment of Erling on Visingsö. I had the opportunity to visit the island in 2016 and can confirm that it lives up to its billing as the island of kings and legends. The fortress of Näs, on the southern tip of the island, was the seat of the twelfth- and thirteenth-century kings of Sweden, and presumably intended as a location that provided great security – though ironically King Karl Sverkersson was killed there in 1167. Little of the fortress survives now, having crumbled into the sea over the centuries, but if its location is any indication, King Knut seemingly felt that Sverre’s request to apprehend and keep Erling was of some significance. The pragmatist in me, of course, wants to argue that the fact that Erling was kept alive, indicates that Knut felt that this was a good chess piece to have and to play if the opportunity arose. More importantly, for the saga author at least, while the stone tower at Näs might have been impregnable, it was, nonetheless, one from which a man could escape. This, Erling promptly did, with the help of the woman who had been feeding him, and he subsequently acquired the byname ‘Steinveggr’ (lit. stone wall) as a commemoration(!) of his incarceration.
Exactly what happened to Erling afterwards is disputed among the sagas, and even among the different versions of the same saga – likely the author(s) didn’t know. Nevertheless, the story has provided me with a great case study and reminded me about that beautiful summer day when I may (or may not) have fallen off my bicycle on a completely straight bit of road going towards Näs, because I was watching the surrounding scenery with iron-age graves, straight oak trees, and stunning views of the lake…