Sweden. 1632, military prephilately. Thirty Years War (1618–1648). A lovely courier letter from to the Swedish Chancellor Axel Oxenstierna presented April 7, 1632 in Mainz (west of Frankfurt a. Main) with a little red seal on back on nice mounted page full of history and knowledge. The Swedish King had come to Mainz in December 1631 and established his headquarter there. Also some history of Oxenstierna and documentation of other Swedish items from this war. Excellent quality for this age. A true postal history exhibition item!