The Palatine Hill, (; Latin: Collis Palatium or Mons Palatinus; Italian: Palatino [palaˈtiːno]) which is the centremost of the Seven Hills of Rome, is one of the most ancient parts of the city and has been called "the first nucleus of the Roman Empire." It stands 40 metres above the Roman Forum, looking down upon it on one side, and upon the Circus Maximus on the other. From the time of Augustus Imperial palaces were built here. Prior to extensions to the Palace of Tiberius and the construction of the Domus Augustana by Domitian, 81-96 AD, the hill was mostly occupied by the houses of the rich. The perimeter measures 2,182 meters and the area is 255,801 square meters or 63 acres, with a circumference of 1,740 meters while the Regionary Catalogues of the fourth century give a perimeter of 11,510 feet or 3,402 meters (equals 131 acres).
The name of the hill is the etymological origin of the word palace and its cognates in other languages (Greek: παλάτιον, Italian: palazzo, French: palais, Spanish: palacio, Portuguese: palácio, German: Palast, Czech: palác, etc.).[a]
The Palatine Hill is also the etymological origin (via the Latin adjective palatinus) of "palatine", a 16th century English adjective that originally signified something pertaining to the Caesar's palace, or someone who is invested with the king's authority. Later its use shifted to a reference to the German Palatinate. The office of the German count palatine (Pfalzgraf) had its origins in the comes palatinus, an earlier office in Merovingian and Carolingian times.
Another modern English word "paladin", came into usage to refer to any distinguished knight (especially one of the Twelve Peers of Charlemagne) under Charlemagne in late renditions of Matter of France.[b]
According to Livy (59 BC – AD 17) the Palatine hill got its name from the Arcadian settlement of Pallantium. More likely, it is derived from the noun palātum "palate"; Ennius uses it once for the "heaven", and it may be connected with the Etruscan word for sky, falad.
Another legend occurring on the Palatine is Hercules' defeat of Cacus after the monster had stolen some cattle. Hercules struck Cacus with his characteristic club so hard that it formed a cleft on the southeast corner of the hill, where later a staircase bearing the name of Cacus was constructed.
Rome has its origins on the Palatine. Excavations show that people have lived in the area since the 10th century BC. Excavations performed on the hill in 1907 and again in 1948 unearthed a collection of huts believed to have been used for funerary purposes between the 9th and 7th century BC approximating the time period when the city of Rome was founded. 
According to Livy, after the immigration of the Sabines and the Albans to Rome, the original Romans lived on the Palatine. The Palatine Hill was also the site of the ancient festival of the Lupercalia.
Many affluent Romans of the Republican period (c.509 BC – 44 BC) had their residences there.
From the start of the Empire (27 BC) Augustus built his palace there and the hill gradually became the exclusive domain of emperors; the ruins of the palaces of at least Augustus (27 BC – 14 AD), Tiberius (14 – 37 AD) and Domitian (81 – 96 AD) can still be seen.
The Palatine Hill is an archaeological site open to the public (requires payment).
Later emperors particularly the Severans made significant additions to the buildings.
The building is located near the Temple of Magna Mater at the western end of the hill, on a lower terrace from the temple. It is notable for its beautiful frescoes.
The House of Tiberius was built by Tiberius, but Tiberius spent much of his time in his palaces in Campania and Capri. It was later incorporated into Nero's Domus Transitoria. Part of it is remains in the current Farnese Gardens.
During Augustus' reign, an area of the Palatine Hill was roped off for a sort of archaeological expedition, which found fragments of Bronze Age pots and tools. He declared this site the "original town of Rome." Modern archaeology has identified evidence of Bronze Age settlement in the area which predates Rome's founding. There is a museum on the Palatine in which artifacts dating from before the official foundation of the City are displayed. The museum also contains Roman statuary.
In July 2006, archaeologists announced the discovery of the Palatine House, which they believe to be the birthplace of Rome's first Emperor, Augustus. Head archaeologist Clementina Panella uncovered a section of corridor and other fragments under Rome's Palatine Hill, which she described on July 20 as "a very ancient aristocratic house." The two story house appears to have been built around an atrium, with frescoed walls and mosaic flooring, and is situated on the slope of the Palatine that overlooks the Colosseum and the Arch of Constantine. The Republican-era houses on the Palatine were overbuilt by later palaces after the Great Fire of Rome (64), but apparently this one was not; the tempting early inference is that it was preserved for a specific and important reason. On the ground floor, three shops opened onto the Via Sacra.
In January 2007, Italian archeologist Irene Iacopi announced that she had probably found the legendary Lupercal cave beneath the remains of Augustus' residence, the Domus Livia (House of Livia) on the Palatine. Archaeologists came across the 16-metre-deep cavity while working to restore the decaying palace. The first photos of the cave show a richly decorated vault encrusted with mosaics and seashells. The Lupercal was probably converted to a sanctuary by Romans in later centuries.
In November 2007 archaeologists unveiled photographs of the cave. Partially collapsed and decorated with seashells and colored marble, the vaulted sanctuary is buried 16 metres inside the Palatine hill. A white eagle was found atop the sanctuary's vault. Most of the sanctuary is collapsed or filled with earth, but laser scans allowed experts to estimate that the circular structure has a height of 8 metres and a diameter of 7.3 metres. Adriano La Regina (former Rome’s archaeological superintendent 1976–2004, professor of Etruscology at Rome’s La Sapienza University), Prof. Fausto Zevi (professor of Roman Archaeology at Rome's La Sapienza University) and Prof. Henner von Hesberg (head of the German Archaeological Institute, Rome) denied the identification of the grotto with Lupercal on topographic and stylistic grounds. They concluded that the grotto is actually a nymphaeum or underground triclinium from Neronian times.