On 15 July 1928 the first German machine-enciphered messages were broadcast by German military radio stations. Polish monitoring stations began intercepting them, and cryptologists in the Polish Cipher Bureau's German section were instructed to try to read them. The effort was fruitless, however, and was eventually abandoned. There remained very slight evidence of the effort, in the form of a few densely written-over sheets of paper and the commercial-model Enigma machine. On 15 January 1929 Major Gwido Langer, after a tour of duty as chief of staff of the 1st Legion Infantry Division, became chief of the Radio-Intelligence Office, and subsequently of the Cipher Bureau. The Bureau's deputy chief, and the chief of its German section ("BS-4"), was Captain Maksymilian Ciężki.