Book excerpt: Throughout the middle and late Republican periods (fourth to first centuries BC) the Romans lived in fear and loathing of the Gauls of northern Italy, caused primarily by their collective historical memory of the destruction of the city of Rome by Gauls in 387 BC. By examining the literary evidence relating to the historical, ethnographic, and geographic writings of Greeks and Romans of the period - focusing on invasion and conflict - this book attempts to answer the questions how and why the Gauls became the deadly enemy of the Romans. Dr Williams also examines the problematic notion of the Gauls as 'Celts' which has been so influential in historical and archaeological accounts of northern Italy in the late pre-Roman Iron Age by modern scholars. The book concludes that ancient literary evidence and modern ethnic presumptions about 'Celts' are not a sound basis for reconstructing either the history of the Romans' interaction with the peoples of northern Italy or for interpreting the material evidence.