Patrick Sims-Williams is Professor of Celtic Studies in the University of Wales, Aberystwyth, and was formerly Reader in Celtic and Anglo-Saxon in the University of Cambridge. He is the author of Religion and Literature in Western England, 600-800 (1990), Britain and Early Christian Europe (1995), and The Celtic Inscriptions of Britain: Phonology and Chronology, c. 400-1200 (2003). He is a co-editor of Ptolemy: Towards a Linguistic Atlas of the Earliest Celtic Place-Names of Europe (2000) and New Approaches to Celtic Place-Names in Ptolemy's Geography (2005), and he edits Cambrian Medieval Celtic Studies. He has been a Fellow of the British Academy since 1996.