Constantine the Great is a titanic figure in Roman, and indeed world history. Most famed for making Christianity the official religion of the Roman Empire (and thus ensuring its survival and spread), and for moving the seat of imperial rule to 'New Rome' (Constantinople), he is most often studied for his religious and political impact. But it is often forgotten that his power and success was made possible by the use of armed force, in an impressive military career which is well worthy of study in its own right. Constantine won victories over external barbarian armies as well as defeating the Roman armies of his internal rivals in civil war. Elizabeth James sets the scene with a discussion of the nature of the Roman army as it emerged in evolved form from the Third Century Crisis, describing the make up of the armies, their weapons and tactics, and the impact of Constantine's policies and reforms. She then examines each of Constantine's campaigns and battles, (including the British campaign which led to his proclamation as emperor at York) to show that he deserves to be remembered as a great general as well as a great emperor. This will be a welcome study of a neglected facet of this historical colossus.