From Wikipedia:
The Pour le Mérite, known informally as the Blue Max (German: Blauer Max),[1] was the Kingdom of Prussia's highest order of merit. It was awarded strictly as a recognition of extraordinary personal achievement, rather than as a general marker of social status or a courtesy-honour, although certain restrictions of social class and military rank were applied. The award was given as both a military (1740-1918) and civil (1740-1810, after 1842 as a separate class) honour.
The award was founded in 1740, by the francophone Frederick the Great; it was intended primarily as a military honour, but was also sometimes given for civil accomplishments. New awards of the military class ceased with the end of the Prussian monarchy in November 1918.