A good example of how the Romans guarded their walls is Hadrian's Wall (Latin: Vallum Aelium or Vallum Hadriani ) which was built in the Roman province of Britannia, beginning in 122 AD during the reign of the emperor Hadrian. There were milecastles with two turrets in between which probably hosted 1,000-1,500 soldiers. There was a fort about every five to ten Roman miles. From north to south, the wall comprised a ditch, wall, military road and vallum (another ditch with adjoining mounds). It is thought that the milecastles were staffed with static garrisons, whereas the forts had patrolling garrisons of infantry and cavalry.
Hadrian's Wall is made up of roughly 80 large Milecastles, 160 smaller Turrets, and an estimated 24 million stones that make up the wall itself.
A good example of how the Romans guarded their walls is Hadrian's Wall (Latin: Vallum Aelium or Vallum Hadriani ) which was built in the Roman province of Britannia, beginning in 122 AD during the reign of the emperor Hadrian. There were milecastles with two turrets in between which probably hosted 1,000-1,500 soldiers. There was a fort about every five to ten Roman miles. From north to south, the wall comprised a ditch, wall, military road and vallum (another ditch with adjoining mounds). It is thought that the milecastles were staffed with static garrisons, whereas the forts had patrolling garrisons of infantry and cavalry.
The borders of the Roman Empire in southeastern Europe was the River Danube. Part of the border in western Europe was the River Rhine . These provided a degree of protection. Garrisons were placed along the banks of the rivers. In an area of Germany between these two rivers the Romans built the limes Germanicus, a 568 km (353 miles) long system of fortifications with a series of walls and at least 58 forts and 900 watchtowers (some of them might not have been recovered by archaeologists. In northern England the Romans built Hadrian's Wall, a wall which was 117.5 km (73 miles) long and run from coast to coast. There were 80 fortlets which could host perhaps 20-30 soldiers (they are called milecastles because they were built at intervals of a Roman mile) which guarded a guarded a gateway through the wall. These were stone watchtowers placed about 1/3 of a Roman mile on ether side of the fortlet. There were 14 to 17 full size forts which could host 500-1,000 troops.