What were the strengths of Roman civilization? How were the Romans able to conceive and sustain a civilization over a period of almost ten centuries?

The main strength of the Roman Empire relies on the solid foundation in which it was created. The Empire was established over the tradition and political sight of the Republic, promoting stability and letting the spread. And the Romans were able to conceive and sustain the empire because they brought ideas from the empires that preceded them - specifically the Persians. The administration of the Empire was structured on a system of local governments subjected to the central power. Each province and conquered territory had its local power which represents the central one.