Novelist and historian Ellis (The Rising of the Moon, 1987; The History of the Irish Working Class, 1973) offers a limpidly penned account of the racially tense, culturally fruitful relationship between the Romans and the Celts of Italy during the growth of the Roman Republic (390-191 B.C.). The Romans' first military encounters with Celts are popularly thought to have been Julius Caesar's conquests of Gaul in the first century B.C. However, as the author points out, Romans encountered the warlike Celts on the Italian peninsula early in the development of the Roman super-state, and their initial experiences did not inspire confidence in the ultimate triumph of Roman arms. In 390 B.C., a Celtic army under a chieftain named Brennus defeated the Roman army in the battle of Allia; the ensuing occupation of Rome lasted seven months, until the Roman Senate bought off the Celts. The legacy of this humiliation, Ellis contends, was an enduring Roman hatred for the Celts that ultimately resulted in Roman destruction of Celtic civilization wherever the Romans found it. The author argues that the Roman-Celtic wars of the 200 years following the battle of Allia determined the course of the Roman Empire. While the ""Celtic terror"" continued to infect northern Italy and menace Rome, the Romans gradually learned to counter the Celtic tactic of massed charges--the Romans lost many battles but in the fateful battle of Telamon (225 B.C.) destroyed a large Celtic army that threatened the peninsula. This victory presaged final Roman triumph, although they continued to have trouble with the Celts during Hannibal's invasion of Italy. Although the Celts were ultimately subjugated and absorbed into Roman society, Ellis argues that they made lasting contributions to Roman literature, culture, and even military science. Writing from a deep knowledge of Celtic culture, Ellis vividly evokes the clash between two proud societies.