The Roman Army
The Roman Army, famed for its discipline, organisation, and innovation in both weapons and tactics, allowed Rome to build and defend a huge empire which for centuries would dominate the Mediterranean world and beyond.
The Legions was considered the most advanced fighting force of its time. Not until Napoleon in the 18th/19th century did an army use the same kind of organisation. In fact Napoleon remodeled the French imperial army on the same lines as the Roman legions. He even took the Eagle as his standard and considered himself as a French Caesar and Emperor.
The Roman Army created the Roman Empire – a huge part of Western Europe – and Rome itself greatly benefited from the riches that the army brought back from its conquered territories.
For further reading I had added the following link on the Roman Army by our friends at the Ancient History Encyclopedia Website.
Below is a video by the History channel on the history of the roman army and why it was such an effective fighting force.