Answer: Plebeians and Patricians.
The patricians were the ruling class of Rome until the early Republic. The relevance of the distinction decreased after the Conflict of the Orders, and by the time of the late Republic and Empire, the title was mostly of only nominal significance.
The plebeians, or plebs, were the common, free citizens of Rome. During the early Republic, plebeians were excluded from magistracies and religious colleges, and were not permitted to know the laws that governed them. They served in the army, but they rarely became military leaders. From 494 to 287, general strikes (part of the Conflict of the Orders) were called by the plebeians who were unhappy with the status quo, which resulted in the creation of new laws and institutions that addressed these complaints.
