7世纪中叶至9世纪初期,总体而言麦西亚的统治者是当时的盎格鲁-撒克逊诸王中最强大的,但编年史却没有为他们冠以这个头衔,普遍认为这是编年史的反麦西亚偏见导致的。《威尔士年鉴》则一直认可诺森布里亚国王是“撒克逊人的国王”,直到716年诺森布里亚的奥斯雷德一世(英语:Osred I of Northumbria)死亡。
Fanning, Steven. "Bede, Imperium, and the Bretwaldas." Speculum 66 (1991): 1–26.
Wormald, Patrick. "Bede, the Bretwaldas and the Origins of the Gens Anglorum." In Ideal and Reality in Frankish and Anglo-Saxon Society, ed. P. Wormald et al. Oxford, 1983. 99–129.
Charles-Edwards, T. M. "The continuation of Bede, s.a. 750. High-kings, kings of Tara and Bretwaldas." In Seanchas. Studies in early and medieval Irish archaeology, history and literature in honour of Francis J. Byrne, ed. Alfred P. Smyth. Dublin: Four Courts, 2000. 137–45.
Dumville, David "The Terminology of Overkingship in Early Anglo-Saxon England." In The Anglo-Saxons from the Migration period to the Eighth Century. An Ethnographic Perspective, ed. J. Hines (1997): 345–65
Keynes, Simon. "Bretwalda." In The Blackwell Encyclopaedia of Anglo-Saxon England, ed. Michael Lapidge et al. Oxford, 1999.
Kirby, D. P. The Making of Early England. London, 1967.
Wormald, Patrick. "Bede, Beowulf and the conversion of the Anglo-Saxon aristocracy." In Bede and Anglo-Saxon England. Papers in honour of the 1300th anniversary of the birth of Bede, ed. R. T. Farrell. BAR, British series 46. 1978. 32–95.
Yorke, Barbara. "The vocabulary of Anglo-Saxon overlordship." Anglo-Saxon Studies in Archaeology and History 2 (1981): 171–200.