Servian Wall in the context of "Oppius"

The Palatine Hill (/ˈpælətaɪn/; Classical Latin: Palatium; Neo-Latin: Collis/Mons Palatinus; Italian: Palatino [palaˈtiːno]), which relative to the seven hills of Rome is the centremost, is one of the most ancient parts of the city; it has been called "the first nucleus of the Roman Empire". The site is now mainly a large open-air museum whilst the Palatine Museum houses many finds from the excavations here and from other ancient Italian sites.

Imperial palaces were built there, starting with Augustus. Before imperial times the hill was mostly occupied by the houses of the rich.

41°53′36″N 12°28′59″E / 41.89333°N 12.48306°E / 41.89333; 12.48306

The Capitolium or Capitoline Hill (/ˈkæpɪtəlaɪn, kəˈpɪt-/ KAP-it-ə-lyne, kə-PIT-; Italian: Campidoglio [kampiˈdɔʎʎo]; Latin: Mons Capitolinus [ˈmõːs kapɪtoːˈliːnʊs]), between the Forum and the Campus Martius, is one of the Seven Hills of Rome.

The seven hills of Rome (Latin: Septem colles/montes Romae, Italian: Sette colli di Roma [ˈsɛtte ˈkɔlli di ˈroːma]) east of the river Tiber form the geographical heart of Rome, within the walls of the city.

The Oppian Hill (Latin, Oppius Mons; Italian: Colle Oppio) is the southern spur of the Esquiline Hill, one of the Seven hills of Rome, Italy. It is separated from the Cispius on the north by the valley of the Suburra, and from the Caelian Hill on the south by the valley of the Colosseum. The Oppius and the Cispius together form the Esquiline plateau just inside the line of the Servian Wall.

In the divisions of the Septimontium (seven hills) Fagutal appears as an independent locality, which implies that originally "Oppius" was strictly applied to this spur except the western end. The northern tip of this western end was also called Carinae, which extended between the Velian Hill and the Clivus Pullius, looked out to the southwest (across the swamps of the Palus Ceroliae towards the Aventine), incorporated the Fagutal and was one of ancient Rome's most exclusive neighborhoods.

The Quirinal Hill (/ˈkwɪrɪnəl/; Latin: Collis Quirinalis; Italian: Quirinale [kwiriˈnaːle]) is one of the Seven Hills of Rome, at the north-east of the city center. It is the location of the official residence of the Italian head of state, who resides in the Quirinal Palace; by metonymy "the Quirinal" has come to stand for the Italian president. The Quirinal Palace has an area of 1.2 million sq ft (11 ha; 28 acres).

Defensive walls are a feature of ancient Roman architecture. The Romans generally fortified cities, rather than building stand-alone fortresses, but there are some fortified camps, such as the Saxon Shore forts like Porchester Castle in England. City walls were already significant in Etruscan architecture, and in the struggle for control of Italy under the early Republic many more were built, using different techniques. These included tightly fitting massive irregular polygonal blocks, shaped to fit exactly in a way reminiscent of later Inca work. The Romans called a simple rampart wall an agger; at this date great height was not necessary. The Servian Wall around Rome was an ambitious project of the early 4th century BC. The wall was up to 10 metres (32.8 ft) in height in places, 3.6 metres (12 ft) wide at its base, 11 km (7 mi) long, and is believed to have had 16 main gates, though many of these are mentioned only from writings, with no other known remains. Some of it had a fossa or ditch in front, and an agger behind, and it was enough to deter Hannibal. Later the Aurelian Wall replaced it, enclosing an expanded city, and using more sophisticated designs, with small forts at intervals.

The Romans walled major cities and towns in areas they saw as vulnerable, and parts of many walls remain incorporated in later defences, as at Córdoba (2nd century BC), Chester (earth and wood in the 70s AD, stone from c. 100), and York (from 70s AD). Strategic walls defending the frontiers of the Empire by running across open country were far rarer, and Hadrian's Wall (from 122) and the Antonine Wall (from 142, abandoned only 8 years after completion) are the most significant examples, both on the Pictish frontier. Most defences of the borders of the Roman Empire relied on systems of forts and roads without attempting a continuous barrier.

The Aurelian Walls (Italian: Mura aureliane) are a line of city walls built between 271 AD and 275 AD in Rome, Italy, during the reign of the Roman Emperor Aurelian. They superseded the earlier Servian Wall built during the 4th century BC.

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. The size of the entire enclosed area is 1,400 hectares (3,500 acres). The wall cut through populated areas: in reality the city at the time embraced 2,400 hectares (5,900 acres). Pliny the Elder in the first century AD suggested that the densely populated areas, extrema tectorum ("the limits of the roofed areas") extended 2.8 kilometres (1.7 mi) from the Golden Milestone in the Forum (Natural History 3.67).

The Esquiline Hill (/ˈɛskwɪlaɪn/; Latin: Collis Esquilinus; Italian: Esquilino [eskwiˈliːno]) is one of the Seven Hills of Rome. Its southernmost cusp is the Oppius (Oppian Hill).

41°54′26.42″N 12°29′55.37″E / 41.9073389°N 12.4987139°E / 41.9073389; 12.4987139

The Colline Gate (Latin Porta Collina) was a landmark in ancient Rome, supposed to have been built by Servius Tullius, semi-legendary king of Rome 578–535 BC. The gate stood at the north end of the Servian Wall, and past it were two important streets, the Via Salaria and Via Nomentana. Within this area the Alta Semita linked the Quirinal with the Porta Carmentalis. Several temples were located near the gate, including temples of Venus Erycina and Fortuna. To a person facing the gate in the 4th century AD, the Gardens of Sallust would have been on the left, with the Baths of Diocletian on the right.

An agger (Latin) is an ancient Roman linear mound or embankment. The word is sometimes applied to fortifications, such as the Agger Servianus, a part of the Servian Wall of Rome, which protected the city on its most vulnerable side, the Campus Esquilinus. It consisted of a double rampart bearing formidable fortifications. In modern usage however, particularly in British archaeology, it is most commonly used to describe the ridge or embankment on which Roman roads were built. The course of a Roman road can often be traced today by the distinctive line of the agger across the landscape and even when destroyed by agriculture, the vestigial mound that can persist has allowed archaeologists in recent years to trace the course of many Roman roads using lidar.

The Murus Terreus Carinarum is an obscure earthwork fortification of the ancient city of Rome known from a passage in the works of Varro. The Murus Terreus may have been a part of Rome's earliest fortifications, often referred to as the Servian Wall. While the location of the Murus Terreus remains unknown and debated, it is thought likely that it belonged to the fortifications of the Oppian Hill, thus placing it between the Carinae and the Subura. Pinza suggested that the works were located on the summit of the Oppian.

The Porta Capena was a gate in the Servian Wall in Rome, Italy.The gate was located in the area of Piazza di Porta Capena, where the Caelian, Palatine and Aventine hills meet. Probably its exact position was between the entrance of Via di Valle delle Camene and the beginning of Via delle Terme di Caracalla (known as the "Archaeological Walk"), facing the curved side of the Circus Maximus.

Nowadays Piazza di Porta Capena hosts the FAO Headquarters. Between 1937 and 2004, it was home to the obelisk of Axum.