Aurelian Walls The Aurelian Walls ( ) are a line of city wall s built between 271 AD and 275 AD in Rome , Italy , during the reign of the Roman Emperors Aurelian and Probus . The walls enclosed all the seven hills of Rome plus the Campus Martius and , on the right bank of the Tiber , the Trastevere district . The river banks within the city limits appear to have been left unfortified , although they were fortified along the Campus Martius . Construction . The full circuit ran for surrounding an area of . The walls were constructed in brick - faced concrete , thick and high , with a square tower every 100 Roman feet ( ) . In the 5th century , remodelling doubled the height of the walls to . By 500 AD , the circuit possessed 383 towers , 7 , 020 crenellation s , 18 main gates , 5 postern gate s , 116 latrine s , and 2 , 066 large external windows . History . By the third century AD , the boundaries of Rome had grown far beyond the area enclosed by the old Servian Wall , built during the Republican period in the late 4th century BC . Rome had remained unfortified during the subsequent centuries of expansion and consolidation . The need for better defences became acute during the crisis of the Third Century , when barbarian tribes flooded through the Germanic frontier and the Roman Army struggled to stop them . In 270 , the barbarian Juthungi and Vandals invaded northern Italy , inflicting a severe defeat on the Romans at Placentia ( modern Piacenza ) before eventually being driven back . Further trouble broke out in Rome itself in the summer of 271 , when the mint workers rose in rebellion . Several thousand people died in the fierce fighting that resulted . Aurelian ' s construction of the walls as an emergency measure was a reaction to the barbarian invasion of 270 ; the historian Aurelius Victor states explicitly that the project aimed to alleviate the city ' s vulnerability . It may also have been intended to send a political signal as a statement that Aurelian trusted that the people of Rome would remain loyal , as well as serving as a public declaration of the emperor ' s firm hold on power . The construction of the walls was by far the largest building project that had taken place in Rome for many decades , and their construction was a concrete statement of the continued strength of Rome . The walls were built in the short time of only five years , though Aurelian himself died before the completion of the project . Progress was accelerated , and money saved , by incorporating existing buildings into the structure . These included the Amphitheatrum Castrense , the Castra Praetoria , the Pyramid of Cestius , and even a section of the Aqua Claudia aqueduct near the Porta Maggiore . As much as a sixth of the walls is estimated to have been composed of pre - existing structures . An area behind the walls was cleared and sentry passages were built to enable it to be reinforced quickly in an emergency . The actual effectiveness of the wall is disputable , given the relatively small size of the city ' s garrison . The entire combined strength of the Praetorian Guard , " cohortes urbanae " , and " vigiles " of Rome was only about 25 , 000 men – far too few to defend the circuit adequately . However , the military intention of the wall was not to withstand prolonged siege warfare ; it was not common for the barbarian armies to besiege cities , as they were insufficiently equipped and provisioned for such a task . Instead , they carried out hit - and - run raids against ill - defended targets . The wall was a deterrent against such tactics . Parts of the wall were doubled in height by Maxentius , who also improved the watch - towers . In 401 , under Honorius , the walls and the gates were improved . At this time , the Tomb of Hadrian across the Tiber was incorporated as a fortress in the city defenses . Totila , king of the Ostrogoth s , decided to destroy the walls in 545 , to remove from the Byzantines the possibility of defending Rome in the ongoing Gothic War . According to Procopius , one - third of the walls were razed . Later use . The Aurelian Walls continued as a significant military defense for the city of Rome until September 20 , 1870 , when the Bersaglieri of the Kingdom of Italy breached the wall near the Porta Pia and captured Rome . The walls also defined the boundary of the city of Rome up until the 19th century , with the built - up area being confined within the walled area . The Aurelian Walls remain remarkably well - preserved today , largely the result of their constant use as Rome ' s primary fortification until the 19th century . The Museo delle Mura near the Porta San Sebastiano offers information on the walls ' construction and how the defenses operated . The best - preserved sections of the walls are to be found from the Muro Torto ( Villa Borghese ) to Corso d ' Italia to Castro Pretorio ; from Porta San Giovanni to Porta Ardeatina ; from Porta Ostiense to the Tiber ; and around Porta San Pancrazio . Gates . List of gates ( " porte " ) , from the northernmost and clockwise : Gates in Trastevere ( from the southernmost and clockwise ) : References . Notes Sources