Although Gallovidians clearly took part in David's campaigning, there is no specific evidence connecting Fergus to the operations until after operations ceased. It is possible that Fergus's attestation of 1136 could have had bearing on Gallovidian participation in the king's campaigning. If Fergus's wife was indeed a bastard of Henry I, Fergus himself had a stake in the unfolding English succession crisis, as she would have been a half-sister of Stephen's opponent, Matilda, whom Henry I had nominated as his royal successor. Explicit confirmation of Fergus's involvement may exist in the terms of the subsequent peace treaty, as Richard Hexham recorded that one of the hostages that was handed over to the English for surety was the son of an earl named Fergus. The fact that there was no Scottish earl of that name suggests that, unless Richard Hexham was mistaken, it was Fergus himself who was referred to. In any case, after this date there is no further evidence of Fergus's involvement in Anglo-Scottish affairs.