The Roman Republic made decisions as a group through the senate and the 2 consuls who made daily decisions
The Romans created a new republican government, created an open market, and people came from all over to live in Rome making the society very diverse.
The Romans lived in two different classes the patricians and the plebeians. The patricians were the upper class and they lived comfortable lives and had bodyguards slaves to attend to them
The plebeians lived without bodyguards or slaves and were typically farmers or merchants
In 312 Emperor Constantine had a vision that converted him to Christianity. He then immediately made it legal to be christian and started the Romans path towards becoming the home of Christianity.
Rome fell from internal and external problems. Internally they relied too much on slave labor and they raised taxes an incredible amount making most people poor. Externally they were attacked by the Huns and other barbarians.
Rome Influenced western civilization with the invention of the republic and the Cesarean calendar. They also revolutionized the sewer with some concepts that are still used today. The Romans also greatly developed the court system