This book brings together new archaeological, historical and palaeoecological approaches to the transition from the Romano-British to medieval Celtic economy between the fourth and ninth centuries AD, re-examining well-known sources of evidence and introducing new material. While the emphasis is on the Celtic-speaking areas of Britain after AD 400, the geographical and chronological scope of the contributions is wide-ranging. The articles include a reassessment of the end of the Romano-British economy, suggesting that the conventional interpretation - a sudden collapse in production in the early fifth century - is incorrect; pollen analysis is a key approach in understanding the end of the agricultural economy, and here, for the first time, all relevant pollen sequences are catalogued and discussed. A fresh investigation into imported pottery and glass and inscribed stone monuments clarifies and understanding of these problematical sources, while the nature of the contacts which brought imports into Britain and Ireland is re-evaluated from new evidence which, together with archaeological material from shipwrecks of AD 400-600 (of which a catalogue is presented here) and historical data, indicate that Byzantine contacts with Britain are unlikely to have been on entirely commercial grounds.