“When war is declared, Truth is the first casualty.”
http://books.google.de/books?id=T2OsAAAAMAAJ&q=%22declared,+truth+is+the+first%22&dq=%22declared,+truth+is+the+first%22&hl=de&sa=X&ei=NNNeT5XTNoSi4gTpuOnRBw&ved=0CDwQ6AEwAQ books.google
This famous quotation is similar to the one Philip Snowden used in his introduction to Truth and the War, by E. D. Morel. London, July 1916: "'Truth,' it has been said, 'is the first casualty of war.'" Samuel Johnson#The Idler (1758-1760) expressed a similar idea: "Among the calamities of war may be justly numbered the diminution of the love of truth, by the falsehoods which interest dictates and credulity encourages." Cf. Aeschylus#Misattributed.
Falsehood in Wartime (1928)