1885, 1pi black and blue, overprinted Type III, vertical pair, tied to back of registered cover to Leipzig by neatly-struck Plovdiv c.d.s. (Sep 30), next-day Sofia transit c.d.s. alongside, Leipzig c.d.s. receiver (Oct 18), a significant cover, paying the 1pi letter rate up to 15g with the 1pi registration fee, sent on the final day of validity of the provisional overprints.
