Austro-Hungarian Invasion 1878 (Sept 23): Stampless cover and full contents from "Lager auf den Höhen Linbach" (Camp on the heights above Linbac) to Mödling, Vienna, sent by Major Albert Hirsch, a Company commander in the 20th Infantry Truppen Division at Pakova struck with small "K.K. FELDPOST EXPOSITUR / No. 4" datestamp (Sept 23). Reverse with Modling arrival cds (Sept 28). Full translation of letter enclosed - "we can see the Turkish bonfires from our Camp...at Tuzla a deputation came with news and there may be skirmishing soon". Field Post Office No. 4 was in use for approximately two months. Slight closed tear at top of envelope but a rare cover. Ex collection Keith Tranmer.