Examine the causes, course, and consequences of united states westward expansion and its growing diplomatic assertiveness (war of 1812, convention of 1818, adams-onis treaty, missouri compromise, monroe doctrine, trail of tears, texas annexation, manifest destiny, oregon territory, mexican american war/mexican cession, california gold rush, compromise of 1850, kansas nebraska act, gadsden purchase).

C. The period when the Roman empire experienced peace and prosperity .

Explanation:

The Pax Romana (Roman Peace) was a time of relative peace and solidness over the Roman Empire which went on for more than 200 years, starting with the rule of Augustus (27 BCE - 14 CE). The point of Augustus and his successors was to ensure law, request, and security inside the domain, regardless of whether this implied isolating it from the remainder of the world and safeguarding, or notwithstanding growing, its fringes through military intercession and victory.