Adam Ledgeway is Professor of Italian and Romance Linguistics and Chair of the Faculty of Modern and Medieval Languages at the University of Cambridge. His research interests are in the comparative history and morphosyntax of the Romance languages, Italian dialectology, syntactic theory and linguistic change. His recent books include From Latin to Romance: Morphosyntactic Typology and Change (2012) and Diachrony and Dialects: Grammatical Change in the Dialects of Italy (co-edited with P. Benincà and N. Vincent, 2014). Ian Roberts is Professor of Linguistics at the University of Cambridge. His research interests are in comparative syntax, set against the background assumptions of Universal Grammar argued for by Noam Chomsky. He currently holds a European Research Council Advanced Grant for a project to investigate a hypothesis as to the way in which grammatical options made available by Universal Grammar are organised. His recent publications include Parametric Variation (co-edited with T. Biberauer, A. Holmberg and M. Sheehan, Cambridge, 2009) and Syntactic Variation: The Dialects of Italy (co-edited with R. D'Alessandro and A. Ledgeway, Cambridge, 2010).