Where did the tradition of flying a flag at half mast in remembrance come from and what is the significance?

Answer 1

It started out as a naval tradition. When the captain of a ship died the rigging would be loose and sloppy until a new captain came aboard and got everything back to standard. Among better crews, pride would keep the rigging proper but they would fly the flag in a 'sloppy' manner to indicate mourning. Eventually this tradition carried over onto land and is now the traditional method for a government to express mourning.