If we talk about Rome and the Roman Republic/Empire, most of us mention about the Roman Army and how great it was.
I am finding it hard to understand why apart from the architecture, the legal and political structures that the Roman Empire left post-mostum to the rest of the world (mostly in Western culture), people still mention the Roman Army despite military strategy has advanced so much since the ancient times.
Some say that some of the strategic advancement in the Roman Army are still being studied and used today.
Some say that it is one of the best armies ever (which I find to pick or pinpoint becuase there were so many armies with their own strategies that it is hard to pick which is the best one).
Some say the Roman Army's emphasis on strategy was what kept the Roman Empire afloat from outside forces (what they often called them as 'barbarians' because during that time, Rome was basically the most civilised of all civilisations)
I am finding it hard to grasp why the Roman Army is still mentioned today even though military strategy and the military occupation has advanced a lot since the ancient times
The Roman Army is still talked about today for a lot of reasons. First of all, it is talked about for the same reason that Alexander the Great or Napoleon are talked about today: what they achieved was amazing and impressive for its context. Neither the Roman Army, Alexander, nor Napoleon would stand up to a modern war, because technology has changed and has drastically modified the way warfare is fought. Yet in their own worlds, each achieved amazing military feats.
Secondly, many of the principles employed by the Roman Army are principles still used today. Flanking and envelopment was a common ancient battle tactic that is still important today. The Romans expertly used combined arms in warfare, using skirmishers, light and heavy infantry, light and heavy cavalry, and artillery and other missile troops to great effect. The Romans were experts at logistics, supplying hundreds of thousands of troops spread along a frontier from Britain to Iraq. The Romans were even experts at propaganda and winning the hearts and minds of people, both domestic and foreign (speaking of foreigners, the barbarians were not called that because they were uncivilized. 'Barbarians' comes from the Greek word barbar, which they used to refer to people who did not speak Greek. They thought their language sounded like people saying 'bah bah bah', so called them barbar. While Rome was larger than barbarian civilisations, they were not called barbarians for that reason).
Thirdly, the Roman Empire was Europe's largest and one of the longest-lived civilizations, and played a huge role in the formation of modern European states and national identities. Thus the Roman Empire features heavily in historical study, and as someone said, I'm forgetting who it was, the Roman state was in many ways engineered to supply the army, rather than the army to protect the state. The army was hugely important to the Empire, being a huge factor in the Empire's expansion and ability to survive for so long. Thus it is heavily featured in historical study.
Fourth, the Roman army is trendy. So much media is dedicated to the Roman army. Books, movies, and tv shows have all been made of the Roman army and fighting in the Roman period. It is a topic that is very approachable by non-historians, which makes it very popular with producers.