Foot Post letter, with inside date Copenhagen 17 May 1806 - with manuscript '125' ledger number and foot post mark in italic 'FP' Type 1 - This is the earliest documented use of the FOOT POST mark and in an astonishing and rarely clean impression like seen on this cover. Besides, this is also the EARLIEST RECORDED letter with a Copenhagen Foot Post mark. The Copenhagen Foot Post commenced operations on 1 March 1806. A truly great rarity the DANISH FOOT POST service.