 Ancient Rome is one of the most famous civilisations in recorded history. First a republic, then an empire. The power of Rome stretched from western Europe to northern Africa. Despite Rome's power and prestige however, there is one region of the world that Rome could never conquer. The northern part of what we today call Scotland. To the Romans, this region was known as Caledonia. This was probably an oversimplification on the part of Roman writers and generals however, as what the Romans called Caledonia was a complex system of different tribes and groups. Unfortunately, we don't know what these people called themselves. Why did the mighty Roman Empire fail to conquer these people however? Well, initially, the Romans had some success. After sending a survey fleet in 79 AD, the most notable incident in the initial period of the Roman campaign in Caledonia took place in 83 AD at the Battle of Mons Grupeus, with this mountain range known as the Grampian Mountains today. We know that the Caledonians raised an army of around 30,000 men to confront a highly trained Roman force of approximately half the size. Despite their inferior numbers, the well trained Roman legions won a decisive victory, with around 10,000 Caledonians thought to have died on this bloody occasion. After victory, the Romans briefly built upon their position by strengthening a series of forts and watchtowers along the Gask Ridge. This was a set of Roman defences that cut through Caledonia, starting as far down as Camlin and stretching diagonally up to Cargill, which is just north of Perth. Roman attention soon turned to another part of the Empire, further east however. In 85 and 86 AD, the Romans suffered defeats against Dacian forces in Transylvania, which is a modern-day Romania. With some Roman troops relocated to the east and under increasing pressure from local forces, the Romans dropped back south to the modern-day Scottish-English border. And herein lies one of the major reasons why Rome failed to fully conquer and hold ancient Scotland, the ferocity of the native people. Rome had to drop back to the Scottish-English border because they were under constant pressure when in Caledonia. The Caledonians are documented to be fierce and brave fighters. The Roman statesman, Daio, described the Caledonians as dowty fighters who were fearsome and dangerous men. Additionally, the Caledonians learned a lesson from the Battle of Mons Gropius that fighting the Romans in a traditional battle was futile. Their strategy shifted, with them engaging more in guerrilla warfare tactics against the occupying Roman force, which proved successful over the coming centuries. In conjunction to the ferocity, the Caledonians may also have proved far too unruly to accept living under the Roman yoke. The ancient inhabitants of Northern Scotland would have had their own customs, traditions, basic legal structure, methods of trade, barter, and may even have had their own currency. After all, the Caledonians had managed to raise an army of 30,000 men, which would have required some level of organisation and societal cohesion. Although some Caledonians probably succumbed to the Romans relatively easily, many did not, as rebellion against the occupying Roman force was a common theme for centuries.