This came up as an incidental matter in a related thread but it deserves its own thread, because it's weird!
Why would Tsar Alexander II, Tsar (OK, Czar if you insist) of all the Russias, wear a Prussian order as his highest decoration? He could have worn a St. George of the highest degree or even a St. Vladimir or Stanislaus or St. John. Why this one, and even appears to have the Black Eagle sash? I know he was related to Germanic princely houses by marriage and ancestry but really, this seems bad form, no?
I know it was common to wear the orders and decorations of foreign countries when wearing the honorary military uniforms of those countries on state visits, etc. but he's wearing the 'unattached' or generic Russian general's mundir, not a Prussian rig.
Any guesses, folks?
Better photo: