The limitanei, meaning respectively "the soldiers in frontier districts" or "the soldiers on the riverbank", were an important part of the late Roman and early Byzantine army after the reorganizations of the late 3rd and early 4th centuries. The limitanei, unlike the Comitatenses, palatīni, and Scholae, garrisoned fortifications along the borders of the Roman Empire and were not normally expected to fight far from their fortifications.
Reconstructed Roman fortifications at Vindolanda. The limitanei would garrison similar forts around the Empire.
Limes is a term used primarily for the Germanic border defence or delimiting system of Ancient Rome marking the borders of the Roman Empire. The term has been extended in modern times to refer to the frontier defences in other parts of the empire, such as in the east and in Africa.
Limes Africanus under Septimius Severus (the frontier of Roman Africa (dark tan) in the late 2nd century AD: Septimius Severus expanded the Limes Tripolitanus dramatically (medium tan), even briefly holding a military presence (light tan) in the Garamantian capital Garama in 203)
Reconstructed east gate of the fort at Welzheim, Germany
Reconstructed wooden tower nearby Rainau, Germany