For centuries africans enslaved other africans. name two later slave trades that transported millions of africans to distant lands to work

The slave trade that went from England to Africa, to America, and then back to England, is otherwise known as the triangular slave trade. England shipped small mirrors, beads, and other little trinkets and knick-knacks to Africa as payment for slaves. Africa then exported those people to America. America then shipped molasses, sugarcane, and other fruits and vegetables to England. The process continually repeated itself until the population of Africa hit an all-time low and some highly intelligent person realized "Oh, wait. These Africans are people, too." 

They were constantly being overlooked as a people and were being controlled by people who weren't really native to their homeland.

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.