The Roman state is the last state of the slave-owning society. The slave-owning social and economic formation reached the peak of its development in the Roman state. That state had different forms of government during its more than thousand-year history: republic and monarchy. Rome imposed its will on the world three times, three times created a unity of peoples. The first time this unity was expressed in the Roman state, the second time in the Roman Catholic Church, the third time in law as a result of reception (imitation). Rome, as a slave state, entered the historical arena later and created more perfect slave relations in form. Roman law operated in Italy, Spain, France, and Byzantium during the feudal social relations. And in Germany, the collection of Justinian's laws only ceased to operate in 1900.
Martin Manukyan (Wed,) studied this question.