- Carolingian Francia, c.700-900
- Norway in the Viking age
- Numismatics and charters
I work on early medieval history, focusing especially upon ninth-century Francia and the contribution made by the charter evidence, and on the coinage evidence for Scandinavia in the Viking age. I have recently completed the Anglo-Saxon Coins in Norway project, publishing 4230 coins and fragments of Anglo-Saxon and later English and Scottish to 1279 in Norwegian museums. I am General Editor of the Medieval European Coinage Project. This British Academy Research Project, based at the Fitzwilliam Museum in Cambridge, is publishing a history of European coinage c.400-1500 in 20 volumes (for details, see the project website at http://www.fitzmuseum.cam.ac.uk/research/mec).