Historic Vintage 3.5X5.25 sepia picture postcard signed in black fountain pen ink by Alexander Ferdinand Ludolf von Quast.  A chip to the lower-left corner, otherwise nice.  (1850-1939 Ferdinand von Quast was a Prussian military officer, and a general in the First World War.

Comes with a full Letter of Authenticity from Todd Mueller Authentics if the item sells for $10 and over.