Democracy - from Greek meaning "rule by the people"
The Roman government was a mix of a democracy and a republic. The Romans took many of their ideas of government from the Greeks. The Roman state was described as the republic and its consuls, or chief magistrates, continued to be appointed even after the establishment of one-man rule under the empire, but in its pure form it lasted only until the beginning of the first century B.C.
At the creation of the republic, supreme power probably resided with a popular assembly, but early on the Senate became very influential, and the traditional formula, which survived for centuries, was S.P.Q.R. - Senatus Populusque Romanus - the Roman Senate and People acting together.
In 133 Tiberius Sempronius Gracchus, and many of his political partisans were killed by his opponents. Since then political murder started to be an accepted tool in politics, so this date tends to be used as the end of democratic system an the beginning of populistic system. Roman democracy had fallen because of the too many conquered countries. Extra income from conquered countries made the richest citizens even more richer, and thus gave them extra political strength.
From 133 BC to more or less end of 2nd century AD the Roman Empire was a populistic country, but diffusion powers launched another crisis that made Roman Empire a feudal state which contiunued until it's fall in about 476 AD.
Renaissance humanism was a cultural movement in Europe beginning in central Italy (particularly Florence) in the last decades of the 14th century giving the rise of democracy in modern national governments.