The Roman Republic began with the overthrow of the Roman Kingdom in 509 BC and ending in 27 BC with the establishment of the Roman Empire under Augustus. It was during this period that Rome’s control expanded from the city’s immediate surroundings to the entire Mediterranean Basin.
Roman society at this time was a cultural mix of Latin, Etruscan and Greek elements, which is especially visible in the Roman Pantheon of gods and goddesses. Its political organisation was strongly influenced by the Greek city states of Magna Graecia in southern Italy, with collective and annual magistracies, overseen by a senate. The top magistrates were the two consuls, who had an extensive range of executive, legislative, judicial, military and religious powers. Other magistricies inclused the praetorship and the aedileship. While there were elections each year, the Republic was not a democracy, but an oligarchy, as a small number of powerful families monopolised the main magistracies. Roman institutions underwent considerable changes throughout the Republic to adapt to the difficulties it faced.
The Roman Republic spent the majority of its existence at war. Its first enemies were its Latin and Etruscan neighbours as well as the Gauls, who even sacked Rome in 387 BC. After the Gallic Sack, it conquered the whole Italian peninsula in a century, which turned the Republic into a major power in the Mediterranean, which brought it into conflict with Carthage, against whom it waged three wars. The Carthaginian general Hannibal famously invaded Italy by crossing the Alps with elephants and inflicted two devastating defeats at Lake Trasimene and Cannae on the Republic, but eventually won the war thanks to Scipio Africanus at the Battle of Zama in 202 BC. With Carthage defeated, Rome became the dominant power of the ancient Mediterranean world and embarked on total conquest of the region. This pitted them against the likes of Macedonia, the Seleucid Empire, Jugurtha, Gaul, Mithridates VI and Cleopatra.
Internally, the Republic experienced a long streak of social and political crises, which ended in several violent civil wars. The Conflict of the Orders, in the 4th c. BC, saw conflict between the patricians and plebeans and finally led to political equality in several stages for the lower classes. The conquests abroad led to a huge inundation of slaves which caused problems for Roman society, which allowed the aristocacy to become richer but was ruinous for the urban poor and peasantry in the countryside. In order to solve this issue, several social reformers, tried to pass agrarian laws, but the Gracchi brothers and Saturninus were murdered by their political opponents. Mass slavery also caused three Servile Wars; the last of them was led by Spartacus, a Thracian gladiator who caused havoc in the Italian peninsula until his defeat in 71 BC.
The 1st c. BC was plagued by the rise of great generals, who exploited their military conquests and loyalty of their soldiers to gain control of Rome. Marius (105–86 BC), then Sulla (82–78 BC) were the first to exploit a weakening Republic and would set out the blueprints for a later series of civil wars; the first between generals Julius Caesar and Pompey the Great. Despite his victory and appointment as dictator for life, Caesar was murdered in 44 BC. Caesar’s heir Octavian and lieutenant Mark Antony defeated Caesar’s assassins Brutus and Cassius in 42 BC, but then turned on each other. The final defeat of Mark Antony alongside his ally and lover Cleopatra at the Battle of Actium in 31 BC, and the Senate’s grant of extraordinary powers to Octavian as Augustus in 27 BC, which made him the first Roman Emperor, ended the Roman Republic.