The abbey of Dundrennan appears to have been founded in about 1142, which in turn places its formation at a time when David had extended his power in the south west. Such a date also places the foundation at about the time Máel Máedoc was in the region, which in turn may hint at his own involvement. In any case, if Fergus and David were involved in the abbey's endowment, the fact that it was colonised by Cistercians from Rievaulx suggests that it was somewhat of a penitential foundation in regard to the infamous Gallovidian contribution at the Battle of the Standard four years previously. Furthermore, the fact that Thurstan himself had been responsible for the English resistance meant that Fergus had warred against his own spiritual overlord, and had almost certainly endured ecclesiastical repercussions as a result. In the eyes of the Cistercians, Fergus and David were both responsible for failing to curb atrocities committed during the campaign, and Fergus himself was held accountable by Walter Daniel's "Vita Ailredi" for thousands of deaths.