Russia 1773 ST PETERSBOVRG (St. Petersburg) Stampless SFL to Verviers Belgium

Stampless folded letter (May 23, 1773), with contents, struck with choice “ST. PETERSBOVRG” straight-line (Dobin 0.01, smaller type), manuscript “Pr. Wesel” instructional notation, rated on reverse 23k for inland and 44k for Prussian transit, an exceptional quality example of this scarce early Russian postmark, on an entire sent during the reign of Catherine the Great, very fine; ex “Nikolai”