The site of the founding of the Roman Kingdom (and eventual Republic and Empire) had a ford where one could cross the river Tiber in central Italy.
The Palatine Hill and hills surrounding it provided easily defensible positions in the wide fertile plain surrounding them. Each of these features contributed to the success of the city.
Romulus was Rome's founder and first king. After he and his twin brother Remus had deposed King Amulius of Alba and reinstated the king's brother and their grandfather Numitor to the throne, they decided to build a city in the area where they had been abandoned as infants. After killing Remus in a dispute, Romulus began building the city on Palatine Hill.
His work began with fortifications. He permitted men of all classes to come to Rome as citizens, including slaves and freemen without distinction.
Romulus was behind one of the most notorious acts in Roman history, the incident commonly known as the rape of the Sabine women. To provide his citizens with wives, Romulus invited the neighboring tribes to a festival in Rome where the Romans committed a mass abduction of young women from among the attendees.
The account varies from 30 to 683 women taken, a significant number for a population of 3,000 Latins (and presumably for the Sabines as well). War broke out when Romulus refused to return the captives. After the Sabines made three unsuccessful attempts to invade the hill settlements of Rome, the women themselves intervened during the Battle of the Lacus Curtius to end the war.
The two peoples were united in a joint kingdom, with Romulus and the Sabine king Titus Tatius sharing the throne.
Romulus established the senate as an advisory council with the appointment of 100 of the most noble men in the community. These men he called patres (from pater, father, head), and their descendants became the patricians.
After Romulus died, there was an interregnum for one year, during which ten men were chosen from the senate governed Rome as successive interreges.
Under popular pressure, the Senate finally chose the Sabine Numa Pompilius to succeed Romulus, on account of his reputation for justice and piety. The choice was accepted by the Curiate Assembly.
He reigned for thirty-seven or thirty-eight years.
According to the legend, Romulus vanished at age fifty-four while reviewing his troops on the Campus Martius. He was reported to have been taken up to Mt. Olympus in a whirlwind and made a god. After initial acceptance by the public, rumors and suspicions of foul play by the patricians began to grow. In particular, some thought that members of the nobility had murdered him, dismembered his body and buried the pieces on their land.
These were set aside after an esteemed nobleman testified that Romulus had come to him in a vision and told him that he was the god Quirinus. He became, not only one of the three major gods of Rome but the very likeness of the city itself.
Numa's reign was marked by peace and religious reform. He constructed a new temple to Janus and, after establishing peace with Rome's neighbors, closed the doors of the temple to indicate a state of peace. They remained closed for the rest of his reign.
Numa Pompilius established the Vestal Virgins at Rome, as well as the Salii, and the flamines for Jupiter, Mars, and Quirinus. He also established the office and duties of Pontifex Maximus. Numa reigned for 43 years.
Tullus Hostilius was as warlike as Romulus had been and completely unlike Numa as he lacked any respect for the gods.
Tullus waged war against Alba Longa, Fidenae and Veii, and the Sabines.
During Tullus's reign, the city of Alba Longa was completely destroyed and Tullus integrated its population into Rome.
Following the mysterious death of Tullus, the Romans elected a peaceful and religious king in his place, Numa's grandson, Ancus Marcius.
Much like his grandfather, Ancus did little to expand the borders of Rome and only fought wars to defend the territory.
Ancus Marcius also built Rome's first prison on Capitoline Hill.
Ancus further fortified the Janiculum Hill on the western bank and built the first bridge across the Tiber River.
Ancus Marcius also founded the port of Ostia on the Tyrrhenian Sea and established Rome's first saltworks, as well as the city's first aqueduct. Rome grew, as Ancus used diplomacy to peacefully unite smaller surrounding cities into an alliance with Rome.
Ancus died a natural death, like his grandfather, after 25 years as king, marking the end of Rome's Latin-Sabine kings.
Lucius Tarquinius Priscus was the fifth king of Rome and the first of Etruscan birth. After immigrating to Rome, he gained favor with Ancus, who later adopted him as a son.
Upon ascending the throne, he waged wars against the Sabines and Etruscans, doubling the size of Rome and bringing great treasures to the city. To accommodate the influx of population, the Aventine and Caelian hills were populated.
Among these were Rome's great sewer systems, the Cloaca Maxima, which he used to drain the swamp-like area between the Seven Hills of Rome.
Priscus was succeeded by his son-in-law Servius Tullius, Rome's second king of Etruscan birth, and the son of a slave.
Like his father-in-law, Servius fought successful wars against the Etruscans. He used the booty to build the first wall all around the Seven Hills of Rome, the pomerium. He also reorganized the army.
Servius Tullius instituted a new constitution, further developing the citizen classes.
He instituted Rome's first census which divided the population into five economic classes and formed the Centuriate Assembly.
After a 44-year reign, Servius was killed in a conspiracy by his daughter Tullia and her husband Lucius Tarquinius Superbus.
The seventh and final king of Rome was Lucius Tarquinius Superbus. He was the son of Priscus and the son-in-law on Servius whom he and his wife had killed.
Tensions came to a head when the king's son, Sextus Tarquinius, raped Lucretia, wife, and daughter to a powerful Roman noble. Lucretia told her relatives about the attack and committed suicide to avoid the dishonor of the episode.
Four men, led by Lucius Junius Brutus, and including Lucius Tarquinius Collatinus, Publius Valerius Poplicola, and Spurius Lucretius Tricipitinus incited a revolution that deposed and expelled Tarquinius and his family from Rome in 509 BC.
Tarquin was viewed so negatively that the word for king, rex, held a negative connotation in the Latin language until the fall of the Roman Empire.
The Gauls destroyed many of Rome's historical records when they sacked the city after the Battle of the Allia in 390 BC (according to Varro; according to Polybius, the battle occurred in 387/6), and what remained eventually fell prey to time or to theft.
With no contemporary records of the kingdom surviving, all accounts of the Roman kings must be carefully questioned.