Roman Republic, which took place over a century from the end of the Punic Wars in 146 BC to the establishment of autocracy and military dictatorship under Julius Caesar after 45 BC, and then Octavian-Augustus from 31 BC, one of the most important questions would be: what were the main causes for its failure? There are no simple answers to that, of course, although almost certainly socioeconomic factors were critical. Of course, for ancient civilizations, hard and fast statistics about population, demography, distribution of wealth and incomes and social castes and classes are few and far between. Historians have the written evidence of contemporary observers, almost always written from an elite or aristocratic viewpoint, and even then many of these records have survived the last 2,000 years in only fragmentary form. In the ancient world, the existing evidence indicates that life was indeed nasty, brutal and short for most people, and that the wealth from the expanding empire was concentrated in the hands of a conservative, aristocratic elite that controlled the Roman Senate, although immediately below them was a rising class of ambitious Equites (knights) who were becoming wealthy from trade, commerce, tax collecting and public office, and that many of these were "new men" from the Italian provinces or even further afield. Certainly they had an interesting in expanding the empire, but also their share of wealth and political power within it. Further down the social scale were classes of small plebeian shopkeepers and peasant smallholders who feared and envied the powers of the Optimates magnates and believed they were actually losing ground to them, politically and economically. By the same token, many of the Italian allies (socii) who mostly lacked the benefits of Roman citizenship until after 89 BC also believed they were making many sacrifices to maintain and expand the empire without obtaining their fair share of the rewards. Even further below them, many of the slaves and serfs obtained nothing at all from Rome but misery, and from time to time they rebelled -- most spectacularly under Spartacus in 73-71 BC.
All of these aggrieved classes and individuals attempted to asset more control over political life, especially in order to obtain a greater share of the available wealth for themselves, especially land. From time to time, they would unite behind charismatic leaders such as Tiberius and Gaius Gracchus, or later military strongmen with their own private armies such as Marius and Julius Caesar. By the end of the Republic, these competing strongmen had become the norm in political life. From a historical point-of-view, the institutions that Rome inherited from the time when it was a small city-state, such as the Senate and assembly of tribes were completely inadequate to govern an empire. Given the limitations of transportation and communication in ancient times, despite the excellent system of roads constructed by the Roman legions, no one could really move faster than the speed of a horse or a sailing ship. There was no scientific, industrial or technological revolution in ancient times that would have enabled an empire that extended from Spain to Arabia to be governed from a central point. About 90% of the population consisted of peasants and slaves who resided in rural areas and the most important economic activity by far was agriculture rather than trade or manufacturing. Even later emperors -- who were essentially military dictators -- struggled to find some formula to hold this vast territory together. From the start, it always displayed strong centrifugal tendencies and was subject to frequent invasions, rebellions, coups and civil wars. In earlier times, the Romans were just as often the victims of invasion as the aggressors, such as the Gallic invasion of 241-20 BC or the devastation wrought on Italy by Hannibal's armies. Only gradually did the Roman Empire expand to include Spain, Gaul, Greece and Asia Minor, and this was not the result of a planned or systematic conquest but rather opportunistic expansion by various elite leaders. Over time, though, it had the effect of undermining the old republic and restoring monarchy and dictatorship.
One of the most important questions to examine would be the effect of the Punic War on the social, political and economic life of Italy. During the Late Republic, the class of small peasant farmers in Sicily and Italy was gradually displaced by large estates run by absentee landowners and slave labor. Perhaps one-third of the population of Italy -- as many as two million people -- were slaves, while a large landless proletariat (prolertarii) crowded into the slums of Rome and other cities. By the end of the Republic, the population of the city of Rome may have been one million, nearly have of which were slaves. In no other part of the empire at this time was the concentration of slave labor and land in the hands of the oligarchic elite so great.
These deteriorating social and economic conditions for the common people had political consequences, which like the conquest and plunder of overseas territory reinforced militarism and authoritarian rule. There were two major slave rebellions in Sicily in 135-32 BC and 104-01 BC that were only put down with great difficulty. Around the same time, the leaders of the plebeian reform party (Populares) in Rome Tiberius and Gaius Gracchus, demanded land reform and improved social welfare for the ordinary citizens. Both men were assassinated by their conservative opponents (Optimates) in 133 and 122 BC, respectively, although later both Julius Caesar and his heir Octavian claimed to be leaders of the popular party and patrons of the common soldiers, peasants, laborers and freed slaves. In this sense, then, the Caesars could claim to be a form of populist dictatorship that offered better opportunities to the Roman masses than the oligarchic elite, no matter that formal democracy did not exist.
One of the most successful slave revolts in history occurred in 73-71 BC in which the former soldier and gladiator Spartacus ranged up and down Italy with a vast army of slave followers from Greece, Gaul and other conquered provinces. After defeating every army fielded against him, Spartacus attempted to escape to Sicily with his slave army, but the combined armies of Crassus and Pompey finally crushed him. In this case, the Roman Empire was almost destroyed before it was officially created, and it required the immense wealth of Crassus, who was already the richest man in Rome, and the return of Pompey's legions from Spain after outing down a revolt there in order to save the system of slavery in Italy.
Political and social instability was constant in the Late Republic, as were rulers like Sulla and Marius who assumed dictatorial powers. The Social War of 91-88 BC was followed by the first dictatorship of Sulla in 88 BC, followed by the dictatorship of Marius and then the second Sulla dictatorship of 82-79 BC. In all cases, assassination or proscription became the norm, as did packing the Senate with loyal followers and rewarding them with the confiscated estates of deceased enemies. Dictators like Sulla, Caesar, Pompey and Octavian rewarded also their followers with land, both in Italy and the colonies overseas. Indeed, one of the benefits of military service was the acquisition of land, money and slaves from thanks to the generosity of victorious commanders.
No matter what its formal structure, a key aspect of the actual government in Rome was based on the elaborate relationships between aristocratic patrons and a plethora of clients and retainers. All successful politicians in Rome devoted part of their daily activities to servicing the needs of clients, and by the Late Republic the major leaders all had private armies whose loyalty was to them personally rather than the state. Those aspiring to the highest positions of leadership such as first consul or dictator had to finance these armies and clients through conquest, such as Caesar's conquest of Gaul (which led to the sale of at least two million inhabitants into slavery) of the failed conquest of Parthia by Crassus -- an adventure that led to his death and the destruction of his army.
In essence, then, the Late Republican was ruled by unstable coalitions of military strongmen who found it useful to maintain the facade and charade of outdated Republican institutions. They did so because many of the Romans, particularly the conservative party, still had a deep aversion to monarchy or the trappings of imperial institutions. Even though the Republic had long since ceased to exist in reality, the illusion remained -- and was even continued by early emperors like Augustus and Tiberius. After Julius Caesar defeated Pompey in the civil war of 49-47 BC, he was in fact a king or emperor in everything but name, although his enemies in the conservative party like Brutus and Cato the Younger assassinated him in 44 BC when he appeared ready to openly proclaim himself king.
Caesar's death opened the door to the final death struggle of the Republic, in which he heir…