who formed the roman constitution?
It emerged from that of the Roman kingdom.
Constitution of the Roman Republic
. The constitution emerged from that of the Roman kingdom, evolved substantively and significantly—almost to the point of unrecognisability—over the almost five hundred years of the republic. 
what was the most powerful lawmaking body in the roman republic Assemblies how many types of assemblies are there? Curiate Assembly, the Centuriate Assembly, and the Tribal Assembly. what is the role of the extraordinary magistrates? The dictator of the extraordinary magistrates had "maius imperium" and total authority to command the state; however, since the dictator generally tried to maintain order, this did not conflict with the responsibilities of the other magistrates, who continued to function during a dictatorship. what is the function of the first assembly? It was ethnic in nature, and thus were organized on the basis of the early Roman family, or, more specifically, on the basis of the thirty original patrician (aristocratic) clans.
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Constitution of the Roman Republic [SEP] Introduction
The constitution of the Roman Republic was a set of unwritten norms and customs which, together with various written laws, guided the procedural governance of the Roman Republic. The constitution emerged from that of the Roman kingdom, evolved substantively and significantly—almost to the point of unrecognisability—over the almost five hundred years of the republic. The collapse of republican government and norms from 133 BC would lead to the rise of Augustus and his principate. The republican constitution can be divided into three main branches: A complex set of checks and balances developed between these three branches. For example, the assemblies theoretically held all power, but were called and governed by the magistrates, who, controlling discussion, exercised dominating influence over them.