Why was trade vital to the time period pax romana?

The Pax Romana (pax is Latin for peace) was a prolonged period of peace in the Roman Empire that lasted for more than two centuries, from about 27 B.C. until around A.D. 180. During this time no other empire or military power achieved victory against the Romans.

The Pax Romana (pax is Latin for peace) was a prolonged period of peace in the Roman Empire that lasted for more than two centuries, from about 27 B.C. until around A.D. 180. During this time no other empire or military power achieved victory against the Romans.

I want to say the first one but I could be wrong