A trade that involves more than one state, and that is, under the constitution, a proper subject of federal law
We were the most concerned about the containment of communism (second answer).
Answer:
In 6th-century Christianity, Roman Emperor Justinian launched a military campaign in Constantinople to reclaim the western provinces from the Germans, starting with North Africa and proceeding to Italy. Though he was temporarily successful in recapturing much of the western Mediterranean he destroyed the urban centers and permanently ruined the economies in much of the West. Rome and other cities were abandoned. In the coming centuries the Western Church, as virtually the only surviving Roman institution in the West, became the only remaining link to Greek culture and civilization.