what regions come under this kingdom?
Tiber, Palatine Hill and hills surrounding it.
Roman Kingdom
The site of the founding of the Roman Kingdom (and eventual Republic and Empire) had a ford where one could cross the river Tiber in central Italy. The Palatine Hill and hills surrounding it provided easily defensible positions in the wide fertile plain surrounding them. 
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. who formed the roman constitution? It emerged from that of the Roman kingdom.
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Roman Kingdom [SEP] Origin
The site of the founding of the Roman Kingdom (and eventual Republic and Empire) had a ford where one could cross the river Tiber in central Italy. The Palatine Hill and hills surrounding it provided easily defensible positions in the wide fertile plain surrounding them. Each of these features contributed to the success of the city. The traditional version of Roman history, which has come down to us principally through Livy (64 or 59 BC – AD 12 or 17), Plutarch (46–120), and Dionysius of Halicarnassus ( 60 BC – after 7 BC), recounts that a series of seven kings ruled the settlement in Rome's first centuries.