Optimates and Populares; according to Cicero in his ‘Republic’ 3,23
“When certain men control the state by virtue of their wealth, their distinction, or any form of power, this is a faction, but they call themselves ‘Optimates.” (the best people)
Infact that title was applied to the clique of more reactionary nobiles and their supporters who were concerned to reserve for themselves the right to control the decisions of the Senate and the electoral and legislative assemblies by the traditional means of amicitiae and clientela.
To an Optimate the theoretical sovereignty of the Roman people should always be subordinate in practice to the authority of the Senate; the Senate should be controlled by those whose family traditions and wealth fitted them to provide the senior magistrates of Rome and to guide their decisions. Any politician who did not enjoy the support of the Optimates, or who wanted to propose reforms or programmes contrary to their interest had to find ways of counter their formidable power. Many of the most successful methods had been demonstrated by the Gracchi brothers Tiberius and Caius during their tribunates of 133 and 123-122, and by C.Marius and the tribune L.Appuleius Saturninus in 103 and 100.
Tribunes had the right of proposing legislation in the council of the Plebs (consilium plebis), which was in fact the Assembly of the People excluding the members of the very few Patrician families. They could also veto the proposals of other magistrates.
As 10 tribunes were elected each year, and they did not require the qualifications of age and previous office which consuls required, it was not difficult for ambitious and active men to secure election.
They could, without the consent of the Senate, get far-reaching legislation passed in the Plebeian council which, on their interpretation of the constitution was perfectly legitimate.
The word Popularis, which is often used as the opposite of Optimate, describes rather the method used by politicians than their policies, which might be designed to further the selfish interest of a few individuals just as much as to put right glaring social injustices.
The populares were by no means a political party, even in the sense that the Optimates were, and, although it is possible to trace a certain continuity of thought and even ideals in the actions of men whom their contemporaries called populares, the faction which opposed the Optimates from time to time nearly always centred round one leading personality, whose motives should not necessarily be construed as democratic or idealistic.
(Pompey the Great (1978), by John Leach)