Conclusion

For both ancients and modern writers, the frontier marked the edge of the Roman Empire, the division between civilization and barbarism. As the anonymous author of the fourth-century de Rebus Bellicis envisaged it,

Above all it must be recognized that wild nations are pressing upon the Roman Empire and howling about it everywhere, and treacherous barbarians, with the cover of natural places, are assailing every frontier [limes]…An unbroken chain of forts will best assure the protection of these frontiers, on the plan that they should be built at intervals of one mile [1,6km], with a solid wall and very strong towers. ³¹⁸