Political evolution of Ancient Rome

Ancient Rome was the first democratic state, and also the only one case when democracy had fallen. So there would be advisable to present its political evolution (at least in my humble opinion).

• First, Rome was feudal state. Probably Rome was an important exporter of crops to Etruscan city-states, and thus noble families have some political privileges under the rule of a few last Etruscan kings. It is very likely that kingdom of Rome was another example of “feudal democracy”, but I have only clues here.
• About 509 BC last king Tarquinius Superbus (Tarquinius the Proud) was defeated by revolution, and Rome started to be populistic republic. These times emerged the two major political powers patricians, and plebeians that fought with each others sometimes using very “dirty” methods. Generally these times Rome was ruled by patricians or some dictators.
• About 499 BC there was the Second Secession, when plebeians went out of the city, and refuse to fight in wars conducted by patrician government. The effect of that strike was “Lex dudecim tabularum” (the Laws of Twelve Tables) - the special law codex that regulated political system of Rome, and organized Rome law system, thus protecting plebeians against patricians abusing poorer citizens thanks to unclear law regulations that have been used before.
• Since then Rome was democracy with two strong political parties: plebeians, and patricians which have very balanced power. Political system was a little complicated but guaranteed good control over state officials. An effect of democracy was very stable expansion of Rome. About 133 BC this small city-state ruled or dominated almost all lands in the Mediterranean region.
• 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 we can use this date 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. And the agrarian crisis destroyed Roman “middle-class”. Finally, after the civil war in 90-89 BC all Roman allies in Italy became Roman citizens. As you can see, democracy in Rome have fallen a few decades before Julius Caesar.
• From 133 BC to more or less end of II century AD Roman Empire was an populistic country. These times Roman Empire had no reasonable opponents, so continued expansion as long as it was possible.
• At the end of II century AD diffusion powers launched another crisis that made Roman Empire an feudal country. The final element of this fall was the edict of emperor Caracalla (212 AD), that gave citizens rights all free people who lived in the Empire.
• Since then till the final fall, the Roman Empire was an feudal country.