In 2011 a hoard of coins and jewellery was discovered near Silverdale, Lancashire, England. One of the coins discovered in this hoard carries the name AIRDECONUT on one side, and the letters DNS (an abbreviation of DOMINUS) REX on the other. DOMINUS REX translates as "the Lord and King". Officials of the British Museum have said the inscription Airdeconut might be a rendering of the Norse name Harthacnut. Experts from the museum have identified that the coin's design relates to coins of the kings Siefredus and Cnut (Sigfroðr and Knútr in Old Norse), who ruled the Viking kingdom of Northumbria jointly between 895 and 905. The coin is also significant since it suggests Airdeconut was a Christian – the reverse inscription DNS (DOMINUS) REX is arranged in a cross.
This coin is the only piece of evidence for the existence of a ruler of Northumbria by the name of Harthacnut. According to Dr Gareth Williams, curator of early medieval coins at the British Museum, the discovery of the existence of Airdeconut represents the first new Medieval king in England discovered for over fifty years and the first previously-unknown Norse king discovered since 1840.
It is likely that Airdeconut was one of several kings who shared power in Viking Northumbria at the start of the tenth century. The period was one of political instability – the ruling Vikings of Dublin were expelled in 902 and some of them came to England. Several of these later reigned over Northumbria as kings in York. There was much conflict between the Anglo-Saxons of Mercia and Wessex and the Vikings of Northumbria in this period. It culminated in the Battle of Tettenhall in 910 when a combined Wessexian-Mercian army dealt a decisive defeat to a Viking army raiding in Mercia, killing several northern kings including Eowils and Halfdan.
- Downham, p. 75
- "Evidence for unknown Viking king Airdeconut found in Lancashire". The Guardian. 14 December 2011. Retrieved 3 March 2015.
- "Viking silver unearthed in England". Independent Online. 15 December 2011. Retrieved 3 March 2015.
- "Viking hoard provides new clues to 'previously unknown ruler'". The Telegraph. 14 December 2011. Retrieved 3 March 2015.
- "Two hoards and one unknown Viking ruler". British Museum. 14 December 2011. Archived from the original on 18 May 2015. Retrieved 3 March 2015.
- "Metal detector forager discovers Viking hoard of silver in Lancashire field". The Australian. 15 December 2011. Retrieved 3 March 2015.
- Robin et al., p. 33
- Cannon and Hargreaves, p. 63–68
- Cannon and Hargreaves, p. 65
- Downham, pp. 87–89
- Cannon, John; Hargreaves, Anne (26 March 2009). The Kings and Queens of Britain. Oxford University Press. ISBN 978-0-19-158028-4.
- Downham, Clare (2007). Viking Kings of Britain and Ireland: The Dynasty of Ívarr to A.D. 1014. Edinburgh: Dunedin Academic Press. ISBN 978-1-903765-89-0.
- Robin, Jim; Smith, Sharon; MacDonald, Fiona; Margeson, Susan M.; Edgeworth, Louise. The Vikings. CUP Archive.