What new system of national government did the delegates agree upon at the constitutional convention of 1787?

Central government system was created. Each State retained its sovereignty, freedom, and independence, and every power, jurisdiction, and right, which is not by this Confederation expressly delegated to the United States, in Congress assembled

Anthropology, archaeology, classics, history, language, law, politics, literature, performing arts, philosophy, religion, and visual arts.

Assemblies do not have written codes of laws. laws are matters for magistrates and courts, not assemblies. codes of law are things such as civil law, criminal law, and constitutional law. what assemblies have are procedures regarding debating, voting and other business they might carry out.  also note that rome had three assemblies: the assembly of the soldiers, the assembly of the tribes, and the plebeian councils.