Final answer:
Romulus was the first king of Rome, who, according to legend, founded the city after killing his brother Remus. His reign marked the beginning of Rome's monarchical period, which lasted until the establishment of the Republic in 509 BCE following the overthrow of Tarquinius Superbus.
Step-by-step explanation:
The very first king of Rome, according to legend, was Romulus. As infants, Romulus and his twin brother Remus were abandoned and, in the legend, they were raised by a she-wolf. Over time, conflicts arose between the two brothers, culminating in Romulus killing Remus, after which he went on to found the city of Rome.
Rome's founding is famously dated to April 21, 753 BCE. Romulus not only founded the city but also started the period of monarchical rule. After his reign, six other kings ruled until the Roman Republic was established with the overthrow of the last king, Tarquinius Superbus, in 509 BCE.
The monarchal system in Rome was eventually rejected due to the fear and wariness of the Romans, including different classes like plebeians, patricians, and senators, toward concentrated power, which could lead to tyranny.
Throughout Roman history, respect for laws, boundaries, and private property was emphasized, and the early stories of Romulus killing Remus and the establishment of Rome encapsulate these values.