The Third Punic War is one of the most important events, because after the past two wars with Carthage, Rome wanted to wipe them out completely, so that they would control all trade in the Mediterranean sea. So in the year 149 BC, Rome waged war against Carthage. This war ended up spelling the doom for Carthage, and with Rome now the king of all trade in the Mediterranean sea. Thanks to Rome winning the war, they brought thousands upon thousands of slaves from Carthage, and this is wear the problem starts. The patricians were able to buy the slaves, and make them work for no pay, while the plebeians could not buy the slaves. So since most people back then were farmers, it caused the amount of food that was being produced to sky rocket. This meant that the value of food went down, and the plebeians money source had just been decreased which caused massive unemployment. The patricians got richer, while the plebeians got poorer. So what occurred is massive amounts of plebeians went to the city to find jobs, but found out that all the jobs were taken, which caused massive poverty, homelessness, and unemployment. This would have a huge effect on the Roman Republic.
This event is important, because the Gracchus brothers saw the difference between the rich and the poor, the patricians and the plebeians. The Gracchus brothers in the year of 133 BC, asked for senate to make a reform to help the plebeians. This would try and help the plebeians, but in the end, it just cause more trouble for the republic. This in a couple of years would lead, the Gracchus brothers to there deaths, where they were murdered. This was just another problem that cause more tension, between the people of Rome.
This is a important event, because this allowed the Gaius to continue with his work, of helping the people. Gaius, did although elect himself, again, which did trouble some of the people. It wouldn't really matter down the road, because in a few years both would be murdered. This event is decently important to the fall of the roman republic.
This is not very important to the fall of the roman republic, although it did have some effect. Marius was a great general, but also became a statesman. He served became consul and served six consecutive terms, although you were only supposed to serve one year. This did have an effect, because the people in power, could elect themselves. Which made the republic a little more corrupt. It also meant someone could stay in power longer then they were supposed to. This event had a little change in the roman republic, but it would still have an effect.
This is one of the important events in Rome, because Sulia became a dictator of Rome, which meant that he could hold all the power, and make it so he held it for life. This gave the republic no purpose, and caused many problems in Rome's republic. Although his rule came to end in 78 BC, but it still had a major effect.
This was a small event, because Spartacus had been leading a slave rebellion for a while, and was causing an problem in Rome and in Italy. Although after some time Crassus decided to put an end this slave rebellion, and ended up defeating Spartacus. This had not a super big effect, its what Spartacus did after this that had a big effect on the Roman republic.
Crassus and Pompey, in the year of 70 BC, went into Rome and seized power. Both were really powerful generals. This had a huge effect on the Rome and its republic, because it allowed Pompey and Crassus, to take power and render the government in Rome useless. This would lead to the downfall of the roman republic, and would create the Roman empire.
This is another important event, that leads to the end of the Roman republic. Pompey, Caesar, and Crassus create the first triumvirate, which ends up failing in a couple of years. The main events as to why it fell, was around 49 BC, a civil war broke out, and there were two sides, one for the republic, and one for the empire. Pompey was for the republic, and Caesar was for the empire. This resulted in Pompey leaving Rome and going east. Also Crassus and Julia both died around 53 BC, and Julia was the only thing holding Pompey in the triumvirate, this led to the civil war. This is how the first triumvirate fell, and how a new path was set for the second triumvirate.
This event is important to the fall of the roman republic because, many plebeians where fond of Caesar, and he was loved by many. The only problem was that the Senate, which was just patricians was not very happy with him. So they set up a plan to kill Caesar. So in the year 44 BC Julius Caesar was assassinated, and this sent the city of Rome and others into deep trouble. Revolts began to happen, and over some time, it would cause Civil war, this had a major effect on Rome, and would give way to the fall of the roman republic.
This is one of the most important event, because this is where the roman republic comes to a end. After failure with the second triumvirate, and many Civil wars, Octavian took the power, and became the first emperor of Rome. This meant that he was a dictator and held all the power, the republic was no more.