Mercia's influence in Kent was limited both before and during Coenred's reign. In a surviving letter (written in 704 or 705), Waldhere, Bishop of London, tells Berhtwald, Archbishop of Canterbury, that Coenred had invited him to a council to be held "about the reconciliation of Ælfthryth". Waldhere refused the invitation as he did not know Berhtwald's opinion on the matter, which was evidently important, although no other reference to it has survived. The letter describes a council to be held at Brentford to mediate between the kings of the East and West Saxons. In the view of the historian Frank Stenton, the letter illuminates the "confused relations of the southern English at a moment when they had no common overlord". The reduced prestige of both Coenred and his successor, Ceolred, may have stirred unrest among the Mercian nobility: Æthelbald was in exile during Ceolred's reign, and the survival of a hostile account of Ceolred may indicate a more general dissatisfaction with the ruling line.