827-870. East Anglia in the 9th century
The narrative sources for East Anglia dry up in the ninth century, even more so than for Northumbria (see entry on 806-66). Beyond the facts that an unnamed East Anglian king sought the help of Ecgberht of Wessex and that the East Angles killed Beornwulf of Mercia in 826, that East Anglia was one of the many targets of Viking raids in 841 and the landing-place of the "Great Heathen Army" in 865, the East Angles leave no traces in narrative history until the martyrdom of King Edmund in 869. It is only from their coins that we can deduce the existence of the kings Æthelstan and Æthelweard, predecessors of Edmund of East Anglia.
The two ship-type coins of Æthelstan seem to date from a revolt after Coenwulf's death in 821. The rest of Æthelstan's coinage follows on directly from the coinage of Ludica of Mercia: no coins of Wiglaf of Mercia were minted in East Anglia, and since we know from other sources that Ludica was killed in 827, that year probably also marks the beginning of Æthelstan's reign as king of an independent East Anglia.
The problems of constructing a skeletal history from the coinage are discussed at length by Pagan. A hoard deposited c.840 and containing (among its East Anglian coins) only coins of King Æthelstan allows the probability that Æthelstan was king at least until 840. A hoard deposited c.860 and containing East Anglian coins of Æthelstan (3), Æthelweard (16), and Edmund (3) suggests that Edmund had come to power shortly before 860, since otherwise we might expect more coins of Edmund. (A hoard deposited c.872, for instance, includes 50 East Anglian coins of Edmund, 5 of Æthelweard, and 2 of Æthelstan.) It would be plausible then to assume that Æthelstan ruled from 827 until the early 840s (perhaps falling in the Viking raids of 841), Æthelweard ruled for the later 840s and early 850s, and Edmund ruled from the later 850s until his death on 20 November 869. Later accounts of Edmund's martyrdom such as the Annals of St Neots place it in his 16th year, and while this appears too late to be accepted as historical evidence it may be noted that the coinage does not contradict a reign-beginning for Edmund in 855.
P. Grierson and M. Blackburn, Medieval European Coinage, 1: The Early Middle Ages (5th-10th centuries) (Cambridge: 1986)
H. Pagan, "The Coinage of the East Anglian Kingdom from 825 to 870", British Numismatic Journal 52 (1982), pp.41-83