History of the Constitution of the Roman Republic
The history of the Constitution of the Roman Republic is a study of the ancient Roman Republic that traces the progression of Roman political development from the founding of the Roman Republic in 509 BC until the founding of the Roman Empire in 27 BC. The constitutional history of the Roman Republic can be divided into five phases. The first phase began with the revolution which overthrew the Roman Kingdom in 509 BC, and the final phase ended with the revolution which overthrew the Roman Republic, and thus created the Roman Empire, in 27 BC. Throughout the history of the republic, the constitutional evolution was driven by the struggle between the aristocracy and the ordinary citizens.
Pax Romana
The Pax Romana (Latin for "Roman Peace") was a long period of relative peace and stability experienced by the Roman Empire. It is traditionally dated as commencing from the accession of Caesar Augustus, founder of the Roman principate, in 27 BCE and concluding in 180 CE with the death of Marcus Aurelius, the last of the "good emperors". Since it was inaugurated by Augustus with the end of the Final War of the Roman Republic, it is sometimes called the Pax Augusta. During this period of approximately 206 years, the Roman empire achieved its greatest territorial extent and its population reached a maximum of up to 70 million people – a third of the world’s population. According to Cassius Dio, the dictatorial reign of Commodus, later followed by the Year of the Five Emperors and the crisis of the third century, marked the descent "from a kingdom of gold to one of iron and rust".