Rǫgnvaldr's involvement in Caithness is also noted by the contemporary English chronicler Roger de Hoveden. According to Roger's "Chronica", after two rounds of negotiations between Haraldr Maddaðarson and William failed, Rǫgnvaldr intervened and bought Caithness from William. The precise date of Rǫgnvaldr's venture is uncertain, although it appears to have occurred in about 1200. Just prior to Rǫgnvaldr's involvement, Roger records that Haraldr Maddaðarson ventured into the Isles where he reinforced himself with an armed fleet, before returning to Orkney and Caithnes, and defeating Haraldr Eiríksson at Wick. If this part of Roger's account refers to military aid being received from Rǫgnvaldr's realm, the fact that Rǫgnvaldr and Haraldr Maddaðarson later became opponents would appear to reveal the fragility of certain of alliances. On the other hand, if Roger's account refers to the domain of the Meic Somairle, it could be evidence that Haraldr Maddaðarson was able to garner support from Rǫgnvaldr's rivals.