The Roman Empire was very good at warfare and military tactics. But the Roman Empire lost wars, even when they had superior military power. Why did Rome lose wars, when they had the best army in the world?

The Roman legions were the best military force in the world for a few centuries. They defeated a whole list of nations, tribes, kingdoms and empires, including the Carthaginians, the Gauls, the Britons, the Persians and the Parthians. Rome conquered all of Europe, North Africa, and parts of Asia. But despite Rome's military power, Rome lost wars. The Dacians defeated the legions in the early 100 AD. The Persians defeated the legions in the late 200 AD. The Goths defeated Rome in 378 AD. The Huns defeated the Goths in 410 AD. Alaric the Goth sacked Rome in 410 AD. The Vandals conquered North Africa in the 400 AD. The Visigoths conquered Gaul in 476 AD. The Huns defeated the legions in 451 AD. The Huns destroyed the Hun kingdom in the 500s AD. The Ostrogoths conquered Italy in 500 AD. The Lombards conquered Italy in 580 AD.<br><br>The answer to this paradox lies in the Roman Republic's unique war fighting strategy. The Roman Republic was very selective about which wars they fought. The Romans never declared war on anyone. They always waited for the enemy to attack them first. When the enemy declared war, Rome always fought defensive battles, on defensive terrain. They never went on conquest, or launched surprise attacks. They never fought outside of Rome's territory. So Rome never got the advantage of the initiative in a battle. But the Romans were masters at defensive battles. They were masters of the science of war. They had the most disciplined, most loyal and most professional army in the world. They had the best military tactics, and the best weapons in the world. They had the greatest engineering and logistical capabilities in the world. They built roads, bridges, walls and fortresses all over the world. They had a huge and efficient logistical system, with thousands of miles of roads and hundreds of bridges. The Roman legions had a great commander, and every legionnaire knew his role and his duty. The Romans fought to defend Rome's territory, and they fought to protect Rome's citizens. Rome never fought to conquer new territory, or to plunder riches. Rome never fought for glory, or for pride. So when Rome fought a defensive battle, Rome usually won. But when Rome fought an offensive war, Rome often lost.<br><br>Another reason Rome lost battles, was because Rome's generals often made tactical errors. Sometimes Rome's generals were incompetent. Sometimes Rome's generals disobeyed the Roman Senate. Sometimes the Roman Senate gave contradictory instructions to the generals. Sometimes the Roman Senate changed the war strategy in the middle of a battle. Sometimes the Roman generals fought defensive battles on bad terrain, against a superior enemy.<br><br>But the main reason for Rome's military defeats, was internal power struggles and corruption. The Roman Republic was plagued by corruption and power struggles. The Roman Senate was a corrupt institution. The Roman Senate was a club for the rich and powerful. The Roman Senate fought against each other, for power and riches. The Roman Senate often made stupid decisions, and gave contradictory instructions. Sometimes the Roman Senate gave instructions to the generals that were against the best interest of Rome. The Roman Senate often neglected the legions, and under funded the military. Sometimes the Roman Senate bought their generals' loyalty, with money or power. Sometimes the Roman generals betrayed Rome, and allied themselves with the enemy. The Roman Republic had many civil wars. The civil wars weakened the legions, and gave the enemy an opportunity to attack Rome.<br><br>The Roman Empire had the most powerful army in the world, for centuries. They had the best military tactics, the best weapons, and the best logistics. They had the greatest engineering capabilities in the world. But despite Rome's military power, the Roman Empire lost battles, and the Roman Empire fell.