Rǫgnvaldr was also responsible for the Welsh translation of mediaeval texts dealing with Charlemagne and Roland. There are ten surviving manuscripts, dating no later than the seventeenth century, which preserve the thirteenth-century "Cân Rolant", the Welsh version of "La chanson de Roland". Along with the Welsh versions of the twelfth-century texts "Historia Karoli Magni et Rotholandi" and "Le Pèlerinage de Charlemagne", "Cân Rolant" comprises part of the Welsh Charlemagne cycle. All but one of the ten manuscripts contain a colophon revealing that Rǫgnvaldr was the impetus behind the original translation. The work appears to have taken place at some point after his accession, and possibly following the marriage of his daughter to Rhodri. The catalyst for the translations is uncertain. During the reign of his contemporary, Hákon Hákonarson, King of Norway, many Anglo-Norman manuscripts were translated into Old Norse, including those that became the thirteenth-century "Karlamagnús saga". "Historia Karoli Magni et Rotholandi" and "Le Pèlerinage de Charlemagne" appear to have been known in Scandinavia by the twelfth century, and it is possible that Rǫgnvaldr became familiar with them whilst in Norway, leading him to commission a translation of his own. On the other hand, he could have also become familiar with the tales whilst in England. Rǫgnvaldr's familial links with the Welsh, and perhaps Cistercian connections between Mann and Wales, may account for his part in the translations into Welsh. The work itself was seemingly carried out at the Ceredigion monastery of Llanbadarn Fawr, once a centre of Welsh scholarship.