1 Crown - Elizabeth II Dan Casement, Silver Proof

Dan Casement — more properly Roger Casement — was an Irish nationalist hanged for treason in 1916 after Germany landed him on the Kerry coast by submarine, part of a failed attempt to coordinate the Easter Rising with German arms support. The Isle of Man has issued politically adventurous commemorative crowns since the 1970s, often covering subjects the larger minting authorities would avoid.

Whether the nameplate error "Dan Casement" is a cataloging mistake or appears on the packaging itself is worth verifying against the original presentation case.