text: Relationships with other kingdoms In addition to the evidence of the Chronicle that Æthelberht was accorded the title of bretwalda, there is evidence of his domination in several of the southern kingdoms of the Heptarchy. In Essex, Æthelberht appears to have been in a position to exercise authority shortly after 604, when his intervention helped in the conversion of King Sæberht of Essex, his nephew, to Christianity. It was Æthelberht, and not Sæberht, who built and endowed St. Pauls in London, where St Paul's Cathedral now stands. Further evidence is provided by Bede, who explicitly describes Æthelberht as Sæberht's overlord.
  Bede describes Æthelberht's relationship with Rædwald, king of East Anglia, in a passage that is not completely clear in meaning. It seems to imply that Rædwald retained ducatus, or military command of his people, even while Æthelberht held imperium. This implies that being a bretwalda usually included holding the military command of other kingdoms and also that it was more than that, since Æthelberht is bretwalda despite Rædwald's control of his own troops. Rædwald was converted to Christianity while in Kent but did not abandon his pagan beliefs; this, together with the fact that he retained military independence, implies that Æthelberht's overlordship of East Anglia was much weaker than his influence with the East Saxons. An alternative interpretation, however, is that the passage in Bede should be translated as "Rædwald, king of the East Angles, who while Æthelberht lived, even conceded to him the military leadership of his people"; if this is Bede's intent, then East Anglia firmly was under Æthelberht's overlordship.