This is one of the most famous of all United States coins.
The information below is primarily from Walter Breen's Comprehensive Encyclopedia.
How and when they were struck is a mystery but all 5 started in the possession of Samuel W. Brown who was Assistant Curator of the Mint Cabinet Collection and also Clerk of Storekeeper of the Mint.
They were kept as a set through August Wagner, Stephen Nagy, Wayte Raymond, Col Green and Burdette Johnson who, along with Eric Newman, apparently broke up the set when disbursing the Green collection in the 1940s. The 5 pieces were reunited for the first time in over 60 years at the 2003 ANA in Baltimore.
The Norweb example, now in the Smithsonian, is inventoried with their pattern coins.
The illustrated example, formerly in the Eliasberg collection, is the finest known and is in a PCGS66 holder.
Photo courtesy of Superior.