The year 2014 marked the 50th anniversary of the first year of operation of the Germany & Colonies Philatelic Society following the amalgamation of the Germany & Colonies Stamp Club (established 1947) and the Stockton German Study Group (1960).
The G&CPS celebrated its inaugural year in 1964 with the first Germania Posta philatelic exhibition held in Stockton.
I have only now seen the message and I would like to respond by ignoring the previous exchange of details. This envelope was used with registration in the Stephansort Post Office on 25.2.92. It was franked 40 Pf. which was the correct rate for a letter under 15gr. + the 20Pf registered fee. The use of the prefranked stationery envelopes in the German Colonies is a contentious subject as they were not issued to the Colony. Further, this envelope is addressed to Roesener a well know creator of philatelic mail in the 1890's. At this time the Germans were keen to get copies of colonial postmarks for their collections and Roesener was one of these enthusiasts. The Steuer handbook dealing with the use and value of forerunners has this to say about the Roesener U 13 in particular: " U13 is not an original forerunner but appears as a typical envelope from Roesener " ( a very free translation by myself ).
I have similar covers sent to East Africa and I believe Roesener sent these envelopes with additional franking under separate cover to the various postmasters with a request that they should be cancelled and posted back to him in Germany. The handwriting on the cover is that of Roesener himself and is the same appearing on my covers to DOA. Mike Farrant