The only substantial accomplishment of the emperor Probus was completing one of these structures.
The only substantial accomplishment of the emperor Probus was completing one of these structures. One of these structures, following the demarcation of the ancient pomerium, was inaugurated by Servius Tullius. The governor Quintus Lollius Urbicus supervised the construction of another of these structures, which was heavily beset by the (*) Caledonians. Another of these structures has "broad" and "narrow" sections, includes milecastles and turrets built by the Second, Sixth, and Twentieth Legions, and extends from Segedunum in the east to Solway Firth on the west, south of a similar structure built by Antoninus Pius. For 10 points, name these defensive fortifications, including one built by Hadrian to mark the northern boundary of the Roman Empire.
The only substantial accomplishment of the emperor Probus was completing one of these structures.
Roman walls [accept Aurelian's wall, Servian wall, Antonine Wall, and Hadrian's wall at any point]