David J. Breeze 
Roman Army [PDF ebook] 

This authoritative short volume introduces readers to the Roman army, its structure, tactics, duties and development. One of the most successful fighting forces that the world has seen, the Roman army was inherited by the emperor Augustus who re-organized it and established its legions in military bases, many of which survived to the end of the empire. He and subsequent emperors used it as a formidable tool for expansion. Soon, however, the army became fossilized on its frontiers and changed from a mobile fighting force to a primarily defensive body. Written by a leading authority on the Roman army and the frontiers it defended and expanded, this is an invaluable book for students at school and university level, as well as a handy guide for general readers with an interest in military history, the rise and development and fall of the Roman legions, and the ancient world.