What is the oldest commissioned naval vessel afloat?

Question

The Battle of Midway, fought between 4 and 7 June 1942, was an important naval battle of the Pacific Campaign of World War II. Why was it called that?

Answer 1

One of these, USS Constitution, a three-masted tall ship, is one of the original six frigates of the United States Navy. It is the oldest naval vessel afloat, and still retains its commission (and hence is listed here), as a special commemoration for that ship alone.