The civilization upon which later Western societies were modeled started on a hill surrounded by marshes in central Italy. The last of 3 Etruscan kings that formed and ruled the Roman Kingdom was overthrown. The clans that managed this in 509 bce politically grappled to a standstill. The resultant Roman Republic lasted 500 years, until exhausted by civil wars.
In the mid-1st century bce Roman general Julius Caesar parlayed his military success in Gaul into dictatorship. The Roman Empire was born. Assassinations and less lethal political intrigue saw an unsteady succession of emperors, capped by the most notorious sociopath in ancient history: Nero.
The overarching structure of Roman society largely followed those that proceeded it: a tiny elite of men lived off the toil of the masses, including an army of slaves which comprised roughly 1/3rd of the population.
The lasting legacy of Rome was its legal regime: the first with laws oriented toward commerce. While 2nd-class citizens, women could own property and engage in business.
Like every society that followed, Rome’s justice system was corrupt. The lower classes were fined and imprisoned while the elite were let off.
The decline of the Roman Empire occurred over 4 centuries. A catalog of ills took their toll: poor political leadership, economic decay, inflation, sovereign debt, lead in the drinking water (from using lead pipes for public water distribution), social corrosion (slavery, debauchery among the elites, disintegration of army discipline, Christianity), and constant incursions by outsiders adhering to the original Roman pillage model. Rome finally fell to Germanic invasion in 476.
A diminished Roman sovereignty held sway in the east for another millennium. This Byzantine Empire eventually fell to invading Turks in 1453, thus engorging the Ottoman Empire, which lasted until 1922.