Frederick the Great, King of Prussia died August 17, 1786.

Frederick the Great (1712-1786)
Issued in 1933 to coincide with the opening session of the new Reichstag in Potsdam

Frederick II (born January 24, 1712, Berlin, Prussia [Germany]—died August 17, 1786, Potsdam, near Berlin) was the king of Prussia (1740–86), a brilliant military campaigner who, in a series of diplomatic stratagems and wars against Austria and other powers, greatly enlarged Prussia’s territories and made Prussia the foremost military power in Europe. An enlightened absolute monarch, he favoured French language and art and built a French Rococo palace, Sanssouci, near Berlin.

… Under his leadership Prussia became one of the great states of Europe. 
Frederick II | Biography, Accomplishments, Wars, Enlightenment, & Facts | Britannica

Last year’s SOD was dedicated to Peter Fechter, a young German murdered while trying to cross the Berlin Wall.

“… he just wanted freedom.”