In early Rome, the patricians (patricii) were a highly privileged aristocratic class of Roman citizens; membership in this class was hereditary and could be achieved only by birth until the end of the Republic. The name probably stems from the Latin word patres, fathers, which was applied to the earliest members of the Roman Senate, from whom the patrician clans claimed descent.
The plebeians (plebei, from plebs, common people) were all the Roman citizens who were not patricians. Originally, patricians were forbidden to marry plebeians, so there was no possibility of movement from one order to another.
The history of the development of the Roman system of government is based on the struggle for power between these two classes (ordines, hence our word orders). In the early years of the Roman Republic, patricians controlled all the religious and political offices; plebeians had no right of appeal against decisions of the patrician government, since no laws were codified or published. The struggle of the plebeians to gain rights and an opportunity for advancement within Roman society and political structures is known as the conflict of orders. The one advantage plebeians had over patricians lay in their numbers, and they used this effectively through the strategy of secession (secessio), withdrawal or the threat of withdrawal from the Roman state during times of crisis. Here are some of the major landmarks in the conflict of orders, which was largely bloodless and free of violence:
What was essentially won during the conflict of orders was the breakdown of an aristocracy of birth and its replacement with an aristocracy that was based on the holding of political offices and on wealth, particularly land-based wealth. The conflict did not destroy the hierarchical, class-based nature of Roman society, nor did it greatly improve the lives or the prospects of the poorer segments of society.Barbara F. McManus