Bidspirit auction | Postal history. Secure letters. Cover

Postal history. Secure letters. Cover of documents sent securely by the Coimbra post office. Marked COIMBRA SEGURO CBR-S4 rar7 in sepia, addressed to Faro. It was sent with postage paid as indicated by 310 in the upper right corner, corresponding to a letter weighing 3 and 2/8 ounces, for the fifth distance. This information is confirmed on the back by the originating post office, which wrote: “Postage paid. 4/03/1822”. Rare