“era” refers to a period of time characterized by events in a chronological order.
“Period” can refer to a short interval of time or a very long interval of time.
So far as I know, there are no prison ships in New York harbor. The closest thing would be the prison on Riker's Island. By "Patriot POWs" do you mean political prisoners of some sort?
Answer: King John of England was forced to sign the Magna Carta stating that the king was not above the law of the land and protecting the rights of the people.
