Final answer:
The Romans allowed those in the conquered provinces to retain their local customs for better governance, stability, practicality, and unity. Assimilation and cultural tolerance helped the Romans maintain control over their vast empire.
Step-by-step explanation:
The Romans allowed those in the conquered provinces to retain their local customs for several reasons. One reason was that the Romans believed in incorporating local elites and communities into their empire for better governance and stability. By allowing the conquered people to continue practicing their customs and traditions, the Romans could maintain control while reducing the likelihood of uprisings and resistance. Another reason was practicality - it would have been difficult for the Romans to enforce their own customs and laws across such a vast empire with diverse cultures. By tolerating local customs, they could focus on more pressing matters such as tax collection and extracting wealth. Lastly, by showcasing some level of cultural tolerance, the Romans could promote a sense of unity and loyalty to the empire. This strategy of assimilation and cultural tolerance helped the Romans maintain control over their vast empire for centuries.