what is the first mentioned one?
The third-longest river in Italy.
Tiber
The Tiber (; ; ) is the third-longest river in Italy and the longest river in Central Italy 
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. what regions come under this kingdom? Tiber, Palatine Hill and hills surrounding it.
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Tiber [SEP] Introduction
The Tiber (; ; ) is the third-longest river in Italy and the longest river in Central Italy , rising in the Apennine Mountains in Emilia-Romagna and flowing through Tuscany, Umbria and Lazio, where it is joined by the river Aniene, to the Tyrrhenian Sea, between Ostia and Fiumicino. It drains a basin estimated at . The river has achieved lasting fame as the main watercourse of the city of Rome, founded on its eastern banks. The river rises at Mount Fumaiolo in central Italy and flows in a generally southerly direction past Perugia and Rome to meet the sea at Ostia.