Cover fr. with 10l orange perf 11 1/2 canc. "ΑΘΗΝΑΙ*3.ΑΠΡ.91" mailed in town. This is the earliest date of circulation of a letter between Athens and Piraeus charged with the local rate of 10 lepta, according to Law Α λ Ν, which was promulgated in 30.3.1891 and put in force in 12.4.1891 according to the telegraphic circulation No 10766/4.4.1891, the postal rate for a letter up to 15 grams between Athens and Piraeus was 10 lepta. A very rare postal history document. (Hellas 75)