Prince Alexander Magnus Friedrich Barclay de Tolly-Weymarn (Russian: ????????? ???????? ???????-??-?????-???????, Alexander Petrovich Barklay-de-Tolli-Veymarn; December 22, 1824 – May 8, 1905), born as Alexander Magnus Friedrich von Weymarn, was a Baltic German military commander who served in the Imperial Russian Army.