The period known as the mid-Republic, ranging roughly from the beginning of the second Punic War to tribunate and murder of Tiberius Gracchus in 133BC, was a time of great expansion in the Roman world. In order to comprehend better the nature of Roman imperialism in this period, it is important to understand how the Romans fought in battle. For decades scholars have argued over the mechanics of mid-Republican infantry combat. In the early twentieth century there was fierce debate among the great German military historians and building on this debate, throughout the last century, a general consensus arose over the mechanics of infantry combat. These models were grand-tactical and produced rather static images of massed groups of highly disciplined soldiers relentlessly advancing against any enemy which crossed their path. So pervasive were these models that this remains the most popular image of the Roman heavy infantry. In the mid '70s pioneering new work sparked a new school of thought in ancient military history and inspired a number of soldier's-eye-view histories, particularly in the field of Greek battle, where there are contemporary accounts, but also some on Roman warfare. Although these new models are persuasive they have not convinced all scholars working on ancient military history and have not yet filtered down into popular consciousness. This book is an attempt to bring these debates back further into the literary field by analysing the combat narratives of the most prolific writer on mid-Republican battle: Livy. In addition it will try both to restore Livy's reputation as a military source and to bridge the current conceptual gap between the literary, archaeological and theoretical approaches to mid-republican infantry combat. The initial two chapters form an extended introduction and justification of the methodology employed. The first discusses the source-based, archaeological, theoretical and psychological parameters of Roman infantry battle, against which any model of combat must be judged. It examines the traditional model and introduces some of the newer ones proposed over the last decade. The second chapter primarily offers a defence of Livy against the charge of crippling military ignorance and a justification for using his accounts as the focus of my analysis. Livy's methodology, use of sources and method of constructing his battle accounts will be examined and briefly contrasted with the techniques of some of his predecessors. The third, fourth and fifth chapters form the bulk of the literary analysis.